YJ Wrangler 32RH Transmission Grinding and Rattling Noise

[zidodcigalah]

Hi, 

I have 32RH trans in 1995 4.0 YJ 150k miles. It works perfectly except there are some noises (probably trans related) that recently started and bother me:

1. After Jeep has been sitting overnight - when I start it in Park, there is some rattling/grinding noise that starts around 2k rpm. This is more pronounced when it is cold outside, like 35F. Noise only occurs in Park and only on 2k+ rpms. I'm not 100% sure that it is gone once everything heats up, it could be that it is just more silent but present. I think this is 100% coming from trans because changing the gear eliminates the noise.
2. Noise when driving - this happened 3-4 times so far. I was driving on a highway and since I have 3.07 and 33s engine was working at 1500 rpm or below all the time. When I got to the incline, I pushed the pedal and engine went to around 2k rpm. Nose similar to first one started, but after 5-6 seconds it was gone and after that no matter how much I pushed the pedal I could not replicate it. It seems to happen only after driving on low rpm for a long time and then pushing the pedal. I could not feel any drivability issues when this happened. I'm not 100% sure this comes from trans but it sounds like that and is definitely related to rpms.. If it was engine I guess I'd have bigger issues.

Trans was never rebuilt. Since I did complete restoration of vehicle a year ago I took transmission out and did following:

1. Adjusted linkages/cables
2. Replaced all seals
3. Changed entire fluid/filter
4. Adjusted both bands
5. Cleaned governor and removed burrs from its housing
6. Cleaned valve body - seemed ok

In the meantime I had to take it out twice because flexplate reluctor ring was slightly out of round and was throwing off CPS signal. Since all replacement plates had issues (poor manufacturing) I took original one to the machine shop where they grinded it to spec. However, I'm not sure if they balanced it.

Having all of this in mind I thought about a couple of things about noise no.1: 

1. Bad check valve - converter fluid drains back. Since converter is not being filled in park, something rattles. I excluded the pump from the equation since it works in any gear. Problem with this is that even after filling the converter in Neutral (and noise goes away immediately after shifting to neutral) noise still occurs in park.
2. Flexplate bolts hitting the dust shield - shield seems a bit bent. However this does not explain why noise is in park but not in neutral.
3. Issues with torque converter - on stall test it was around 2k rpm which by FSM seems to be OK, so I'm not sure about it..

Am I missing something here? 

 

[Moses Ludel]

zidodcigalah...My first picks would be the anti-drainback valve to the torque converter or a clogged cooler issue—or both.  All RH/RE transmissions have the inherent flaw of earlier 3-speed RWD Chrysler transmissions (904, 999 and 727):  By valve body design, there is no lube pressure or fluid flow to the torque converter and front pump bushing when the transmission is in Park.  These transmissions rely solely on the anti-drainback valve to keep the converter fluid full.  When the valve fails or sticks open, the front pump bushing runs without fluid in Park.  Eventually, the front pump bushing burns up.

Here is my comprehensive coverage of this issue.  Sonnax has the cure for Chrysler RWD RE/RH transmissions.  Our 48RE (truck purchased new) became symptomatic by not moving immediately when shifted from Park to drive after being parked for long periods.  I caught the problem immediately before any front pump damage occurred:

https://www.4wdmechanix.com/Survival-Upgrades-for-Jeep-and-Dodge-Ram-Automatic-Transmissions?r=1

These are additional mods I made later, some applying only to the overdrive versions:

https://www.4wdmechanix.com/ram-truck-47re-and-48re-transmission-in-chassis-survival-upgrades-from-bd-diesel-performance/

The other issue, whether the front pump is damaged or not, would be the torque converter itself.  The converter may have issues.  If you wind up replacing the front pump or pump bushing, I would get a rebuilt converter at the same time.  Clean/flush the cooler properly, too.  If you don't perform the Sonnax upgrade(s), install a new anti-drainback valve.

If you do the Sonnax upgrades to the valve body, Sonnax recommends removal of the anti-drainback valve once you have full-pressure lube to the converter and front pump in Park.  I left the anti-drainback valve in place because it is part of the 2005 Ram OEM hose to the cooler.  The valve is not restricting flow and is likely stuck open.  If I change the cooler and hose/fittings, I will likely eliminate the anti-drainback valve.  Sonnax full-pressure lube to the converter in Park is the solution.

I found this and other AT cooler flushing products at Summit Racing.  Read the reviews and listings for similar products:

https://www.summitracing.com/parts/atp-at200

Moses

[zidodcigalah]

Thanks Moses. I'm aware of the design flaw. I will test fluid circulation after drainback valve and after cooler to check for restrictions. The only symptom that is missing so that I can be 100% sure that valve is the problem is delayed engagement. I don't feel any delay, even after 3-4 days...

Could bushing damage cause huge damage in other parts of the transmission system? I'm thinking about scratches on it, not complete failure and breakage. I took some photos while I was doing a vehicle rebuild and I can't see any huge damage on front bushing, maybe slight scratches that to me seem normal for 150k vehicle.

I will try to make a video of the noise and put it here so it can be helpful for someone else with the same issue.

[Moses Ludel]

zidodcigalah...Looking forward to hearing the noise in a video...It's possible the converter stays filled enough to not produce the delay.  A very low converter fluid level creates the delay issue.  If you rule out the front pump bushing, there could be a converter unit issue.

Yes, the main issue with the front pump bushing would be clearance.  (Scratches might indicate too much bushing clearance or fluid bleeding off and not lubricating the front pump bushing.)  Too much clearance, generally from wear, could create noise or front pump rattle. 

Keep in mind that these transmissions also have a history of starving for fluid and pressure on steep inclines.  The filter/pickup does not stay submerged enough to draw fluid.  The converter, front pump and apply units (bands and clutch packs) will suffer from lack of fluid pressure and flow.  Does that sound familiar?

Moses

[zidodcigalah]

Well I finally found some time to check up on this. To be honest, inside vehicle it sounds like rattle while on this video it sounds more like pump. 

Here is the link to video: https://www.youtube.com/watch?v=cGtHNTRaNAI 

This is cold start, and after starting vehicle I kept it around 2000rpm. The clunk you hear occasionally is me switching from Park to Neutral - instantly as I switch to Neutral (or any other position) noise disappears. As soon as I switch back to Park it is there again. Noise seems a bit more silent after driving couple of miles.

I took it for a 60 miles ride. Since I have 3.07 gearing and 33 inch tires, when I'm cruising it is around 1300rpm. If I cruise for 5-10 mins and then give it more throttle on uphill (so it downshifts to 2nd and 2000+rpm) - same noise appears but after 3-4 seconds it is gone and won't happen again unless I repeat the same steps.

Last time I had transmission out, I drove it 3 miles with 1,5 pints of fluid less than max.. I'm not sure if this made the problem worse, but noise in Park was already there before that.

[Moses Ludel]

Zidodcigalah...Good audio/video capture...A failing or failed anti-drainback valve may have started this entire problem.  Your Park to Neutral end of noise phenomenon is likely the converter recharging when you move the manual valve in the valve body from Park to Neutral:  The pump bushing gets charged with oil again.  When the bushing is dry or without enough fluid pressure to stabilize the pump rotor, the pump rattles and buzzes. 

At this stage, the front pump is damaged.  The noise sounds like a classic front pump rattle from a worn front pump bushing and the metal-to-metal grating within the pump.  The bushing wear begins from running dry while in Park mode (likely because the anti-drainback valve was not holding).  As a rule, when the bushing wears enough, it takes out the pump.  Low pump pressure results from the pump wear, and this compounds the problem, making it even more difficult to refill the converter.

Low pump pressure could be your issue when you tip in the throttle at low speeds and the noise occurs.  Before replacing the pump and/or converter, I would run a hydraulic pressure test, using the factory criteria for "normal" pressure at specific engine rpm.  I believe you will discover low pump and hydraulic system pressures.  This will help establish a baseline for the work ahead.

Unless you want to go another round with a new anti-drainback valve, I would do the Sonnax valve body upgrades that I suggested.  That will provide full fluid pressure and flow to the converter when in Park.  Keep in mind that the front pump and bushing metal has run through the system and likely contaminated the oil cooler.  Flush or replace the cooler.

Note:  It might be cheaper to replace the entire radiator and cooler assembly.  I bought a new OEM replacement radiator through Summit Racing for $72, and it came with a new cooler built in.  The plastic side tank radiator has lasted for over 60K miles and still works fine.  The manufacturer builds OEM radiators at Mexico.  Works for me. 

An automatic transmission is a closed system and should only pick up fluid through the filter.  However, when an internal part fails, especially the front pump or converter, the interior components get contaminated.  Abrasive debris winds up in the converter and cooler.

If hydraulic pressure tests low, make sure the clutches and bands are not worn out.  (Test for no slippage on shifts or under load.)  If you suspect band and clutch frictions wear, it's time for dissassembly, thorough cleaning and a bench rebuild of the entire unit.  That's not as extreme as it sounds.  A rebuild kit for a 32RH is relatively inexpensive.  You need basic, universal automatic transmission tools like a K-D clutch spring compressor, a press and improvised sleeves or collars for carefully replacing worn bushings.  The 32RH is basic 904/999 Chrysler RWD architecture dating to the sixties.

Moses 

[zidodcigalah]

Thanks a lot Moses, all of this makes perfect sense... I really can't thank you enough for helping me on this. I guess I'll have to face the inevitable

Since I'm from Europe, ordering/finding spare parts is quite problematic and expensive because of high shipping costs and duties, so I will first try to determine the scope of the damage. For now I don't feel any slippage (even when the noise is present while driving). I will do hydraulic tests and check if line pressure is below spec (probably is). 

1. If pressure is low and pump is shot - do I have to replace converter too? I was thinking about replacing entire pump/seals, flushing cooler and reusing converter.
2. In case of some wonder where pressure is still within specs - could I get away with only front bushing/seals replacement for now? In this scenario, I'd rather do pump when time comes for entire trans overhaul

In any case, Sonnax upgrades are a must. Now, even replacing manual valve would eliminate that noise in Park, but still that would only mask real problem until I repeat that low speed scenario. I will keep you updated, someone might find this useful.

Thanks again for helping me on this and multiple other occasions. Your forums might not have membership base like some other ones, but it has invaluable knowledge and content thanks to you.

[Moses Ludel]

zidodcigalah...You're welcome...It's always good to know your options and the possible parts damage.  To begin, let's discuss the least expensive get by or "survival" approach, knowing that a rebuild is likely down the road. 

Recommendation:  USE THE FACTORY SERVICE MANUAL WHEN ATTEMPTING THIS WORK.  YOU WILL BETTER UNDERSTAND THE FUNCTIONS, SEQUENCING, DISASSEMBLY AND ASSEMBLY OF COMPONENTS.  THE USE OF CORRECT TOOLS IS ILLUSTRATED THROUGHOUT THE CHAPTER ON 30RH/32RH TRANSMISSION REBUILDING.  eBay is one source for a used factory service manual, there is usually a print copy or duplicate CD (PDF format) available.

Check hydraulic pressures before doing any other work.  Use the factory service manual test methods and pressure guidelines.  If pressure is marginal (on the low side), take the transmission out of the chassis with the converter attached, as described in the shop manual.  This is the practical method of removal.  Hold the converter in place within the converter housing.  I use strands of mechanics wire and a block of wood against the converter hub to keep the converter from sliding out of the pump and off the reaction shaft.  Inspect the flexplate and bolts to be sure that loose flexplate flange bolts or a cracked flexplate are not involved in the rattling noise.

Once the transmission is safely out of the chassis, remove the converter carefully from the transmission.  If the converter has been acting okay, you can get the unit flushed while it is separate from the transmission.  This is not the same as rebuilding, and by design, you will never clean a converter thoroughly by "flushing".  Eventually, you will need to have the converter unit rebuilt, which can be done at Europe.  Rebuilding a torque converter means cutting the shell in half on the centerline/weld seam, removing the internal parts, repairing/replacing damaged pieces, rewelding the shell halves together, then balancing the assembly.

If no converter or flexplate damage is evident, I would target the front pump next.  You can carefully remove the front pump by itself.  To do this, first tighten the front band to prevent the internal parts (drum, clutch, etc.) from sliding out the front of the case.  (If these parts slide out, you might be disassembling the transmission completely to get them back in place.)  The front pump can be removed with two slide hammers.  Do not try to pull on one side of the pump at a time, the pump will cock and bind.  Remove the mounting bolts and install the two slide hammers in the threaded locations designed for these slide hammer pullers.  Carefully and evenly tug the pump forward and loose. 

Disassemble and rebuild the pump.  If the gears are still reusable (doubtful but remotely possible), you can restore the pump with a new pump bushing;  if needed, a sleeve repair kit can also be installed.  Inspect for wear, and make sure the gears are within tolerance.  Replace the gears if necessary.  Assemble the pump with new seals and gasket, do not use sealant on the new pump mounting gasket.

The interlocking sealing rings at the rear of the pump require care as you reinstall the pump evenly and without excess force.  Align parts carefully;  slight loosening of the front band may be necessary to center up parts during the pump installation but do not loosen the band prematurely.  Be sure the drum, clutch and other parts do not drift forward during pump installation.  

If you find that you want to rebuild the entire transmission at this time, I quickly came up with this Omix-ADA rebuild kit for $186 USD, the free shipping is presumably within the U.S.  This is one U.S. retailer, there are many, including NAPA Auto Parts:

OMIX-ADA 19001.04 JEEP WRANGLER TJ/YJ AUTOMATIC TRANSMISSION REBUILD KIT

https://jeepsarelife.com/omix-ada-19001-04-automatic-transmission-rebuild-kit

The Chrysler transmission rebuild kits often cover many model years.  Your transmission's architecture is found in cars, light trucks and later Jeep models.  The 904 dates to the early sixties although Chrysler warns not to use early parts in the later 30RH/32RH transmissions.  From Europe, you may find rebuild kits available from Turkey, Israel and elsewhere in the Middle East since Raybestos has been a quality clutch frictions source built around the globe. 

The kit shown at the link includes bushings.  It is possible to change out transmission bushings with a bottle jack press or sometimes an arbor press.  You can improvise on the collars or sleeves needed to remove and replace bushings.  Make sure to align bushing oil holes with the case, do not apply excessive force to aluminum castings.  Use the OEM bushing positions as a guide when pressing.  I use Sunnen B200L to prevent galling and to reduce risk of bind during bushing press operation.

 https://goodson.com/products/sunnen-press-fit-lubricant

The more difficult parts to source would be the front pump assembly and converter.  Yes, you want a rebuilt converter if you rebuild the transmission.  Rebuilding the original pump may be a necessity.  A parts source, surprisingly with a lot of coverage for this transmission, is Rock Auto.  See the listing below.  I'm not clear what the international/VAT and other issues might be, but Rock Auto pricing is often the best available in the U.S.  Note the listing for a front pump sleeve repair kit and bushing.  If your pump gears are okay (a surprise) and there is excess wear at the pump casting, you may be able to resleeve the pump casting then rebush it:

https://www.rockauto.com/en/catalog/jeep,1995,wrangler,4.0l+l6,1185274,transmission-automatic

A relatively inexpensive tool that works for compressing clutches and changing frictions is the K-D tool below (mine has lasted years) and the less expensive versions like the CTA tool:

https://www.amazon.com/KD-Tool-Transmission-Compressor-Automatic/dp/B000WZWGK0/ref=sr_1_1

https://www.amazon.com/CTA-Tools-6500-Transmission-Compressor/dp/B00JHKZGOO/ref=sr_1_2

Moses

 

 

[zidodcigalah]

Moses, thanks for this detailed guide. I finally found some time to do hydraulic test. The specs for my transmission is 54-60psi and up to 90-96psi line pressure at full throttle in position "2" and 1000 rpm. I only did this test since main suspect is pump - if I understood well this test is enough to detect failing pump. I could not find any details if this test should be performed with transmission fluid hot or cold.

I put a jack underneath and removed one rear wheel, connected gauge to trans line pressure port, disconnected throttle cable, started engine and set it idle at 1000rpm with my SnapOn MT2500. 

Unfortunately I only had 500psi gauge, and I had a bit of dripping at line port connection (was unable to seal this), I'm not sure if this can affect readings. Gauge scale is not good enough for this task but needle seems to be between 50-55psi and a hair under or at 90psi at full throttle. I'm also attaching a video (because of angle between camera and gauge readings might look higher/lower than they really are). In best case scenario, these values are close to or at lower limits. Is this a sign of bad pump that needs replacement or these values would be even less in that case?

Video link: https://www.youtube.com/watch?v=PQ3zCpgfmKs

[Moses Ludel]

zidodcigalah...You're on the right track.  In the FSM tests that you are using, there is a "Test 4", transmission in Reverse.  This is a true test of pump output pressure.  The test:  "This test checks pump output, pressure regulation and the front clutch and rear servo circuits.  Use 300 PSI Pessure Test Gauge for this test."  Your 500 psi gauge is fine for the test, reasonably accurate.

Using the rear servo port, follow the procedure for Test 4.  You will be running the engine at 1600 rpm and in Reverse.  Be very careful about your vehicle positioning.  I am not comfortable with your jack under one wheel routine.  Can you use 2WD mode and place safe stands under the rear axle at each side to get both wheels off the ground?  This is a lot of rpm and torque applied in reverse.

I prefer at least warm transmission fluid.  Transmission fluid will warm up fast if you do a Stall Test with the transmission.  Do not stall for too long, the test puts a heavy load on the converter and other parts.  Band adjustment should be correct before performing a stall test...If the transmission and converter fail a stall test, you know there is already a problem with the converter overrun clutch or the ability of the transmission's front and rear clutches to hold, which could be worn clutches and/or not enough fluid apply pressure.  Stall test instructions are in the FSM...Warm fluid is better, but make sure you can handle the gauge and not get burned from the exhaust and such.  Let me know that you have the FSM and Stall Test instructions to follow.  If your metallic rattling noise occurs very clearly during a Stall Test, that could indicate a torque converter defect.

When you know that you are safe, follow these steps for Test 4:

1)  Connect pressure test gauge to rear servo port.  [Looking at the rear of the transmission above the oil pan, the rear servo pressure port is at the right side, to the right of the tailhousing/adapter.  The pipe plug faces directly toward the rear.]

2)  Start and run engine at 1600 rpm for the test. 

3)  Move valve body selector lever four detents rearward from full forward position.  This is Reverse range.

4)  Move throttle lever [this is the kickdown or throttle pressure lever, not the engine throttle!] all the way forward then all the way rearward and note the gauge readings.

5)  Pressure should be 145-175 psi with the [throttle pressure] lever forward and increases to 230-280 PSI as lever moves rearward.

This is a valid test because it better reflects the pump's output capacity.  Your other tests are within reasonable range (a bit low but that could be due to the drip/leak).  However, those readings do not reflect the pump's full output.  Let's see what this test turns up before taking the next step.

Moses 

 

[zidodcigalah]

Well, I did rear servo pressure test and stall test. This time I put jacks under both wheels and under differential case. Vehicle was running at 1600-1650 rpm  in reverse, and I disconnected throttle valve cable. The results with trans fluid warmed up are following:

1. Stall test: 2100-2200 rpm. No rattling or any unusual noise.

2. Rear servo: needle bouncing between 150-160psi. When moving lever pressure keeps rising but in the end it starts to quickly bounce between 200-300psi. Occasionally it stops around 250-260psi but it is only fraction of a second. I'm not sure if this is gauge related or pump is unable to keep steady pressure... Even after running test for 10 mins results were always the same, so I'm not sure if this is air in gauge/hose or pump. No leakage at test port this time 

Bands were adjusted about a year ago.

[zidodcigalah]

Forgot to mention, gauge is not liquid filled, I'm not sure if there is any dampening.

[Moses Ludel]

zidodcigalah...First-off, the shuddering gauge may hold a valuable clue.  Yes, a liquid filled gauge would provide a more stable needle, but there may be more to this.  The good news is the pressures.  They look okay.  Better yet, the stall test does not point to a distinct converter problem like the overrunning clutch.

So, we know a few things:

1)  The pump is working and able to reach suitable pressure.

2)  The overrunning clutch in the converter is not defective and the engine has a slightly high side but okay stall speed (should be 1700-2100 according to the FSM).  There was no "slip" of clutches during the stall test.  This would be indicated by the engine speed flaring up beyond normal stall range.

3)  Your noise does sound like the front pump—a metallic rattle.

I gave thought to all you did initially and since.  You have been very thorough with a professional approach.  My first response was straightforward based upon the Park to Neutral stoppage of the noise, which points to the classic anti-drainback issue that runs the front pump dry.  Typically, the pump bushing becomes damaged from running dry in Park and so forth.  We avoided an immediate transmission removal, and that may have paid off.

The gauge cast a new light on the converter fill issue and noise.  You are missing a key symptom in the anti-drainback problem.  When the drainback valve fails or sticks open, there is a delay when shifting from Park directly to any gear.  This is due to the lack of available fluid in the clutch and band apply circuits.  The transmission acts as if there is no fluid being picked up or allowing the circuits to function.  Damage occurs just like running the transmission low on fluid.

If you do not experience the hesitation or delay when shifting out of Park to a gear, the anti-drainback valve is likely working.  After parking overnight, when there is a delay of engagement during a shift from Park directly to a gear (not stopping in Neutral), the delay is from the converter being filled (anti-drainback valve issue), which delays the fluid flow to the gear apply circuits.
If the only symptoms occurring are 1) the rattle without an obvious delay when shifting directly to a gear from Park and 2) the gauge flutter, I would look for a cavitation or aeration issue.

I ran heavy equipment years ago and worked with hydraulic pumps and cylinders.  When there is fluid cavitation or aeration, the entire system will rattle, hoses shake violently and the pump can make a loud, metallic noise.  This rapid surge and release of pressure can appear on a pressure gauge as severe flutter or hammering.  The gauge type (dry or liquid filled) can matter, so we need to rule out a gauge problem.  What you describe, however, does sound like more than needle "flutter" and could be cavitation or aeration hammering.  The gauge sensation, if reasonably accurate, is a steady hammering or pounding.

Here is an excellent explanation of the difference between cavitation and aeration:

https://www.hydraulicspneumatics.com/technologies/maintenance/article/21884872/cavitation-or-aeration-you-can-hear-the-difference

Cavitation and aeration require a leak source that creates an air gap(s) in the fluid.  Pump pressure can be normal but the air gaps create the hammering effect and possible rattle in the pump.  Let's consider some sources for air getting into the fluid stream, which can become exaggerated with the steady flow of fluid into the converter:

1)  The simplest air source is when the fluid pickup filter has an air leak between the filter and valve body.  This usually shows up shortly after a fluid and filter change.  If the mounting screws loosen over time, this can also start an air leak.  A filter gasket (if used) or O-ring seal can become misaligned or damaged, creating an air leak.

2)  Valve body leak between the separator plates or valve body junction and the transmission case.  Misalignment or warpage of cast plates or the steel separator(s) can also create an air source.  Loose valve body attachment bolts that need re-torque to specification can create air leaks.  Bolts that loosen over time can lead to leaks.

3)  An air leak into the system from a cracked case or fluid passageway (rare and unlikely though possible), any leak on the suction side of the pump;  the pump or pump mounting gasket to the transmission case can be defective and draw air.  An air leak usually means a fluid leak but not necessarily;  a poor fit between the pump housing and transmission case may draw air yet not leak fluid.  If the pump has never been removed, there is less likelihood of a gasket or pump housing leak.

The point here is that you need an air source to put air gaps into the fluid.  The low speed throttle that leads to a rattle when you tip in the throttle, or the rattle when the converter begins to fill as you pull out of Park, each could be clues.  If you are not experiencing gear engagement delay when shifting from Park directly to Drive (1, 2 or Drive) or Reverse, you may have a pump rattle caused by air in the fluid.

See whether you have the Park directly to gear issue after the Jeep has set overnight.  If not, there is likely no drainback valve issue.  Hunt down an air leak source in the fluid lines, filter and valve body.  Try the easier fixes first:  re-torque the valve body bolts and be certain the fluid filter is not drawing air at the filter-to-valve body junction.  If the symptom disappears, try another servo port/Reverse gauge test.  See whether fluid pressure readings stabilize.  The servo port test in Reverse is a better view of the pump function.  Try your current gauge first before using a liquid filled gauge.

Moses

 

[zidodcigalah]

I really appreciate all of your replies. I did remove valve body (but did not disassemble it), and this rattle in Park happened sometime after that (not sure if it happened immediately as it is much more noticeable in cold weather). As far as I know, pump was never removed. I will check filter/valve body for possible leaks. In case that it doesn't solve the problem I will probably drop the transmission again and check front bushing and front pump gear clearance.

Yesterday I saw that fluid level was 1/3 inch above MAX (checked in neutral after driving 30 miles). I read somewhere that fluid above max will be churned by planetary - which in turn creates bubbles. So this might be the reason why rattle on low throttle appeared, as it was not present before. However this does not explain noise in Park as nothing moves at that point.

Anyway, I plan to keep this Jeep for years so at some point transmission rebuild will be necessary. I think I found a good deal on 32RH rebuild kit on ebay for 160$. It contains Red Eagle frictions, Kolene steels, front band, pump bushing and all gaskets/seals. Same supplier also has Sonnax manual and PR valve. I'm still waiting for a reply if they sell pump rebuild kit - I saw they have kit for A518 with front bushing, gear set and seals for 50$. This is a good option for international orders as one supplier provides everything thus minimizing shipping costs, and shipping time is OK. Here is a link to it, please remove it if it is not compliant with forum rules: https://www.ebay.com/itm/Fits-Dodge-A904-TF-6-Transmission-Red-Eagle-Performance-Master-L2-Rebuild-Kit/202573760811

Thank you for your help, I will post results here once I finish working on this issue. I'm an IT guy so if there is anything from that domain that you need help with, feel free to message me

 

 

[Moses Ludel]

zidodcigalah...You're welcome...The valve body to transmission fasteners may have loosened or the filter could be an issue.  Easy to confirm by dropping the pan.  If you want to avoid changing fresh fluid again, catch the fluid in a clean drain pan.  In my early days of automatic transmission work, some OEM shop manuals recommended reusing fresher fluid by running it through 100-mesh brass or stainless steel wire cloth.  I buy this cloth from MSCDirect, you should have a local supplier at Europe.  100 x 100-mesh was essentially the oil pickup screen mesh size on vintage automatic transmissions.  You can go up or down in opening size.  Running fluid through the mesh is a good way to identify the fine debris:

https://www.mscdirect.com/product/details/52431319

The fluid overfill can actually cause aeration of fluid.  Parts churning aeration is the reason for an engine crankcase windage tray...We can guess whether air bubbles would survive a pass through the filter.  Regardless, it's always best not to overfill an automatic transmission.  Overfill increases internal pressure in the transmission and can overload or blow out seals. 

From our exchanges, I can tell that you are committed to the Jeep.  You'll work your way through the Park noise issue, I'm sure.

The kit on eBay looks thorough.  The illustrated parts caught my attention, as there is a cone shaped filter depicted at the lower right.  This type filter typically is at the front pump and can cause intermittent fluid flow if packed with debris.  I revisited parts illustrations of the 904 (as far back as Mopar's 1981 catalog listings for Jeep) and could not find this cone filter.  It does not appear in our FSMs for the 30RH/32RH either.  Not sure if the eBay rebuild kit's coverage dates to an even earlier 904 application.  The pan gasket shape looks typical Chrysler. 

One concern, and you likely caught it when reviewing the FSM, is Mopar's mention that the 32RH/30RH units went through a design revision and to beware of parts differences between the earlier (presumably 904/999) units and  your transmission.  Make certain the rebuild kit will work for your 32RH.  The price is right, the kit looks complete for the usual rebuild.  Confirm the fitment.

We can look into the interchange between the A518 front pump and your 32RH front pump.  The A518 is derivative of the A727 unit, which is larger than the 904.  We can compare front pump part numbers between the A518 and a 32RH when you are ready to order.  Below is a Mopar parts schematic diagram for your front pump.

Keep us posted on this one.  We covered a lot of ground with our exchange.  One more possibility, a long shot but worth a check, is excessive crankshaft endplay from a worn thrust bearing or crankshaft cheeks.  This can create noise in itself or cause parts interference further back at the transmission.  This is an unlikely issue but easy to check:  Push the crankshaft rearward at the front damper/pulley;  pry the crankshaft forward while measuring endplay with a dial indicator.  You can use a block of wood at the pry point (timing cover or whatever) and place pry force at the back of the damper.  You're looking for crankshaft fore-and-aft movement.  The endplay specification is in your FSM.

Thanks for the IT insight and offer...You use an MT2500 and would find automotive lab scopes (Pico, Autel Maxiscope, etc.) interesting.  These tools are capable of pinpoint, millisecond wave form diagnostics and troubleshooting.  This is the breakthrough for modern engine and electrical/electronic troubleshooting and diagnostics.  I am planning a how-to video series on scope functions and ways to take full advantage of a PC-based scope.

Moses

 

 

[zidodcigalah]

Couple of updates on this thread. I did notice some lag during initial start. Once vehicle has been sitting overnight on slight incline, it would take around a second or two to get into reverse or drive. After that it is almost instant.

I ordered Sonnax manual and pressure regulator valve and will install them and remove adb valve completely as it might be causing restriction. If that doesn't solve the problem, I'll do complete rebuild once trans totally fails :)

[Moses Ludel]

zidodcigalah...Good call on the Sonnax kit.  Sonnax actually recommends removing the anti-drain back valve once you have full pressure running to the converter in Park.  If you drill down at the Sonnax website, there is either a footnote or directions that suggest removal of the anti-drain back valve after this valve body modification.  We are doing any Chrysler A727/A904 derivative RWD transmission a big favor by charging the converter in Park.  

The second or two delay is enough delay to indicate that the converter is draining back when the Jeep parks.  That condition with the transmission in Park can starve the front pump bushing.  It will be interesting to see what these valve body modifications do for the original rattle in Park at 2K rpm.  Let's be optimistic and assume you caught this in time and that the pump and front pump bushing are not damaged.

Let us know the results!

Moses

[zidodcigalah]

Hi Moses, 

I recently got Sonnax valves. I plan to drop trans pan soon and replace them while removing anti-drainback valve and verifying band adjustment. I still have one concern - TCC. That rattling issue is still there - but it seems to have some sort of pattern. 

Noise only happens just after trans downshifts to 2nd if I put heavy load on engine when the TCC is engaged and trans is in 3rd speed (not every time, but it happens only under those circumstances). If I put trans in position 2 I'm unable to reproduce issue. Also, if I disconnect TCC relay so TCC never engages, I'm unable to reproduce it. TCC might be related to this but not locking up or upshifting to 3rd also means higher rpms which might prevent the issue.

If I'm going uphill, TCC won't disengage until I push throttle pedal around half way. It seems that it takes too much throttle for it to unlock when under load which chokes the engine since I have 3.07 gears and 33s. Another thing I noticed on flat roads - after TCC locks, if I release throttle pedal and apply light throttle afterwards engine RPMS flare up to 1500 rpm and then drop to 1200. It doesn't feel like slip - it looks like TCC disengaged after releasing throttle, and once throttle is applied again it did not lock immediately. If I disconnect TCC relay none of this will happen and part throttle downshift seems to be much easier and better. I'm not sure if this is normal behavior - I thought that TCC will unlock immediately when vehicle is not cruising and is under load.

If I understand well, TCC solenoid is controlled by PCM and powered thru relay. TPS, vehicle speed and coolant temp are main inputs for PCM. I verified all inputs with scanner, and TV cable is adjusted. I guess all variables related to transmission itself are OK since it behaves perfectly when TCC relay is disconnected. I cannot verify when PCM activates TCC solenoid since that information is not present on scanner. I was thinking about connecting light bulb to relay terminal so that I can see under what circumstances lockup happens. Is it possible that PCM controls relay correctly but something in valve body is causing this abnormal throttle to unlock (if it is abnormal at all)?

[Moses Ludel]

Hi, zidodcigalah!...Interesting behavior of the TCC circuit.  The governor and TCC may have an issue with the 3.07 gears and 33" tires.  That combination keeps rpm low and engine load higher.  This could cause a shift timing problem.  The MAP sensor and other signals call for a shift but the governor speed is low due to the gearing and tire diameter.

I have the opposite issue with my 48RE:  The axle gearing is 4.56.  Even with 35" or 37" diameter tires, I have a harsh downshift unless I slow gradually and allow the governor to sync with the electronic shift signals.  (If the engine and transmission are cold, the governor is off line and all shifts behave correctly.)  I have the Sonnax valves, which direct more volume flow to the converter.  When the powertrain is cold (under 50-degrees F), the shifts up and down are smooth, no harsh downshift.  Warm up, and the harsh downshift comes into play.

Before addressing or compensating for what might be a governor speed and gearing issue, I would do the valve body upgrades.  This may or may not correct the issue.  The torque converter could be involved, but not likely;  this is more likely a governor and road speed mismatch.  The PCM may not know what to do with these mismatched signals.

Moses

[zidodcigalah]

Hi! It took a while but I finally got the transmission out. Still it was working ok (no slippage, pressure around normal) but noise became more and more frequent.

When I dropped the pan, other than gray sludge that was present I also saw some chunks that are either aluminium or brass (they don't stick to the magnet). I disasembled, cleaned and inspected valve body. Everything seems normal there, but two check balls (rear servo and rear clutch) were missing?? There is also an option that I lost them, but I know for sure that this valve body was opened at least once before and I really took a good look at the channels before cleaning out the remaining atf. Also one of the check balls had different color so I'm not sure if someone before lost 3 and added that one.

Anyway, I inspected torque converter and hub and they seem fine, no abnormal scratches (can't feel them with the fingernails). Couldn't take a good look at pump bushing but it doesn't seem in bad shape (will know better once I remove pump assembly).

I'm wondering where this metal chunks might came from? Afaik, only aluminium part beside valve body is transmission housing. Some of the shavings are black on one side and bright yellow on other.

[Moses Ludel]

zidodcigalah...You're thorough as usual.  The missing balls do need to be found.  The colored ball(s) are often intended to distinguish a ball size that is different than the others.  I can see the silvery metal, and it looks like aluminum.  The yellow pieces would be brass. 

Brass, if not very fine, is from bushings like the front pump or bronze thrust washers.  Aluminum, as you share, can be from the transmission case or valve body.  I would look at the accumulator pistons and clutch apply bores in the transmission case.  The accumulator pistons often bind in these bores or chafe the bore over time.  Look for accumulator damage and accumulator bore damage.  (These are the band apply bores.) 

Other aluminum sources would be the band adjuster threads, again part of the aluminum transmission case, and the gear train clutch pistons or plates.  These piston/plates are #4 and #26 in the Mopar parts schematic for your transmission (below):

If you have the FSM, you have this photo of the valve body ball positions.  Note that there should be seven check balls total.  One is 11/32" diameter;  the other six are 1/4" diameter.  Measure the diameters to confirm size:

When you have the teardown completed, check all thrusts, the bores and edges of the clutch basket.  Look at clutch steel and friction plates plus the clutch pressure plates for metal sloughing.  You'll have more details and clarity.

Moses

[zidodcigalah]

Thanks Moses. Will post back once I finish teardown. 

Regarding check balls, based on FSM that I have there are 9 balls total - 7 in upper part of valve body (the ones that you sent) and two more below separator plate.. Those two are missing. All of them are some sort of plastic. I couldn't find any info regarding their size but based on bores they seem to be 1/4".

I googled a bit and found kits for 10$ of sonnax plastic 1/4" check balls. I was thinking about buying that set and replacing all of them except that 11/32". Here is the URL for that set: https://www.sonnax.com/parts/1689-checkball . Only doubt that I have is that there is no a904 or 32RH listed, but I guess they are made of same/similar material like the ones I originaly had in valve body.

[Moses Ludel]

zidodcigalah...The photo I provided was only the valve body balls as per my 1994 Mopar FSM for the YJ/XJ models.  (I have the print version of the factory manual.)  Below is  photo revealing the two balls you describe in the "transfer plate".  One check ball is the rear clutch check ball, the other is the rear servo check ball.  Each, as you note, would be necessary.  Interesting that they were missing, which could affect clutch and servo functions .

Sonnax 0.250" balls look good, they are "imidized" plastic, similar to OEM.  You should be fine with this set as long as you have the 11/32" ball.  Did you trial fit a 1/4" ball in the transfer plate locations?  Is that correct ball size for the rear clutch check ball and rear servo check ball?

 

Glad you caught the two missing check balls.  Any previously rebuilt transmission needs the layout of parts and a thorough accounting for each piece.  I looked in the Mopar Parts Catalog for the 1995 YJ Wrangler, and the 32RH valve body related replacement parts show only the manual lever check ball.  These balls do last a very long time in aluminum castings.

Good thing Sonnax exists!  Plastic is used for a reason.  Hard chrome balls are available, but they would be harder on aluminum castings.

Will it take a long time to receive your Sonnax parts?  Did you order any of the valve body or accumulator upgrade parts?

Moses

[zidodcigalah]

Yup, I do have 11/32. I couldn't find any info on those transfer plate balls in manuals but I found a manual for Transgo shift kits and all balls except 11/32 are listed as same (1/4").

I received SONNAX pressure regulator valve and manual valve cuple of months ago but was to lazy to take the transmission apart  Replaced those already, but with the recent findings I'm probably gonna need some more parts apart from missing check balls

[zidodcigalah]

Regarding delivery times, it took between 3-4 weeks thru USPS Priority international. I guess in normal situation it would've arrived at least 1 week sooner

[Moses Ludel]

Have you compressed the clutches to release spring pressure yet?  Years ago I purchased a universal K-D automatic transmission spring compressor that has worked on all of the assemblies I've built since (Ford, GM, Chrysler, etc.).  I checked to see whether you can still get the tool.  You can:

https://www.amazon.com/KD-Tool-Transmission-Compressor-Automatic/dp/B000WZWGK0

There are now some interesting, less expensive alternatives.  This one caught my attention:

https://www.amazon.com/dp/B011SBI1DW/ref=sspa_dk_detail_0

Some improvise with a large C-clamp or a hydraulic press, but even for one job, these niche compressor tools can save time and help prevent parts damage.

[zidodcigalah]

Haven't compressed clutches yet. I removed pump today together with front and rear clutches. Before removal I checked input shaft endplay and it was within limits (1.2 mm, spec is from 0.56 - 2.31mm). So far I haven't found anything obvious...

After pump removal, I disassembled it and checked bushing along with pump gears. No scoring, nothing I could feel with the nails. Couldn't think of a way to measure inner to outer gear tooth clearance with feeler gauge or how to check if bushing is still within spec. I checked clearances with feeler gauges and they are within spec albeit a bit on a higher side:

• outer gear to pump 0.16mm, spec is from 0.08 to 0.19mm
• gears to straight edge 0.04mm, spec is from 0.01 to 0.06mm

Based on this pump seems to be still fine. Not sure but I should skip pump rebuild at this point?

Front band seems to still have enough friction material. Also, I removed snap rings and checked frictions and metal plates. Front clutch seemed fine, I could even see serials/dates stamped on them. No burn marks on steels. Tried to verify clearance, not sure if I did it correctly but got smth around 2.9mm (spec is 1.70 to 3.40 mm).

Rear clutch is barely within spec (1.10mm, spec is 0.64-1.14mm), I have seen 5-6 spots around 5mm in diameter on steels that look like burn marks, frictions seem fine but some of them are a bit darker (blackish) around center than those from front clutch.

Could not see those aluminium pistons from clutches as I haven't compressed them yet.. Side that I could see now had scratches but again I couldn't feel them with fingernails. After removal of front servo and accumulator piston I did not find any damage to piston or bores in trans case.

However, I did find some damage to sun gear shell and front clutch drum, not sure if this is significant: 
 

Almost all teeth had these marks, they look beaten not like a piece broke off even though it looks like that in pictures.

 

[Moses Ludel]

Seem my comment below, Zidodcigalah...Moses

23 hours ago, zidodcigalah said:

Haven't compressed clutches yet. I removed pump today together with front and rear clutches. Before removal I checked input shaft endplay and it was within limits (1.2 mm, spec is from 0.56 - 2.31mm). So far I haven't found anything obvious...

Good end play measurement...You're good here.

After pump removal, I disassembled it and checked bushing along with pump gears. No scoring, nothing I could feel with the nails. Couldn't think of a way to measure inner to outer gear tooth clearance with feeler gauge or how to check if bushing is still within spec. I checked clearances with feeler gauges and they are within spec albeit a bit on a higher side:

• outer gear to pump 0.16mm, spec is from 0.08 to 0.19mm
• gears to straight edge 0.04mm, spec is from 0.01 to 0.06mm

Check the bushing on its riding surface.  Keeping the parts parallel, I check for runout or clearance.  Also try rocking the pump without great pressure.  If there is no sign of wear or scoring, the parts would still be usable.  As a point, however, I always replace the front pump bushing and seal.  If you do replace the bushing, be careful as you press in the new bushing.  (I use a press, not a hand driver on these bronze bushings.  I often use hand driver bushing adapters with my bottle jack press.  Sometimes I use the driver handle, adapter and the press.  What I never do is drive bronze bushings into place with a hammer.)  Avoid rolling or peening the edge of the bushing while applying press force.  I lube the outer bushing with Sunnen B200L (or equivalent) to prevent galling.  Make sure each shaft turns freely, without excess clearance, inside a new bushing.  Fitted correctly, automatic transmission bushings do not require reaming or burnishing.

Based on this pump seems to be still fine. Not sure but I should skip pump rebuild at this point?

Again, I replace the pump bushing and seal.  If there is no sign of bushing wear, you have an option.  (The bushing could have been replaced during the rebuild that you believe took place previously.)  Keep in mind that these 904 derivative Chrysler RWD transmissions are notorious for front pump bushing wear during startup in Park if the anti-drainback valve is not working properly.  Rule out bushing wear if you do reuse the front pump bushing.  Carefully replace the front pump seal in any case.

Front band seems to still have enough friction material. Also, I removed snap rings and checked frictions and metal plates. Front clutch seemed fine, I could even see serials/dates stamped on them. No burn marks on steels. Tried to verify clearance, not sure if I did it correctly but got smth around 2.9mm (spec is 1.70 to 3.40 mm).

If you invest in a thorough rebuild kit, you will get all frictions and steel plates, a new flex/kickdown band, bushings and thrusts.  Some kits include bushings, some do not.  The kit below is thorough, including steel plates.  It does have all the bushings.  You'll need to decide which level kit you need based on the wear in your transmission:

https://www.quadratec.com/products/52023_13_07.htm

Rear clutch is barely within spec (1.10mm, spec is 0.64-1.14mm), I have seen 5-6 spots around 5mm in diameter on steels that look like burn marks, frictions seem fine but some of them are a bit darker (blackish) around center than those from front clutch.

If steel plates are acceptable, new frictions should restore this specification.  The current reading is a sign of friction wear.  However, steel plates should not have wear marks, grooving or indications of heat damage.  You describe the "burn marks".  In my view, this sign would justify changing the steels.  

Could not see those aluminium pistons from clutches as I haven't compressed them yet.. Side that I could see now had scratches but again I couldn't feel them with fingernails. After removal of front servo and accumulator piston I did not find any damage to piston or bores in trans case.

Yea, no piston bore damage.  I replace the OE pistons with anodized aluminum pistons and special seals found in the kit from Sonnax.  (See my article on the RE/RH upgrades.)

However, I did find some damage to sun gear shell and front clutch drum, not sure if this is significant:

This wear is not unusual.  It's from tang drive force between these parts—as you suggest, not from "pounding"...Check the debris to see whether it matches these parts or the aluminum clutch pressure plates when you get to them.  If you consider reusing these parts, there will be more movement or clearance than stock.  Check the gap against the factory clearance.  You can see the original sun gear driving shell's slot edges.  Compare this gap to the gap at the highest wear point.  If not an excessive difference, these parts could still be usable.  At the very least, deburr any wear points that could break off or slough into the pan. 

If I were "restoring" this transmission, I would replace these parts with new or "good used" pieces.  When I did restoration work on vintage transmissions, Fatsco was a reliable source for reasonably priced NOS and good used parts.  Professionally, I would have replaced the mating sun gear shell and front clutch drum/retainer. 

The rattle that you experienced could be between these two parts.  When in Park, the 32RH is in Neutral with the parking pawl locked.  These clutch units have no pressure applied.  Here, the rattle of worn parts could occur.  Another noise point could be when the clutches apply pressure.  Test the check balls and seats in the clutch apply circuits.  Use compressed air to check the clutch applies for pressure, holding ability and leakage.  Make sure the valve body plates are flat (check on a piece of plate glass).  Test for any causes of clutch plate slippage.

 
 

Almost all teeth had these marks, they look beaten not like a piece broke off even though it looks like that in pictures.

 

 

[zidodcigalah]

Thanks Moses. Will check everything you said. When I finished engine rebuild I installed new flexplate bolts, they originaly had black coating but heads are looking like stainless steels now. Looks like they were hitting/scratching dust plate. Now this can be source of noise but it does not explain debris and noise that is present in PARK only or under special conditions in D.

Even though this trans was running, most of the parts in this trans are barely within spec so I'm gonna invest in rebuild kit. Based on bushing/thrust washer wear I will check what kit I'm gonna need. These are Raybestos RED and ALTO Red. They list them as "high performance". I've seen that Altos are flat, no grooves on frictions, not sure if that is important. Not sure if it's worth investing in these or in OEM Raybestos, Alto or BorgWarner. (years might not be correct but stores have proper bushings and bands and number of clutches for 1995 separately)

https://www.oregonperformancetransmission.com/product/OPT-A904-RBHP.html
https://norcaltransmissionparts.com/027901hp-l2-dodge-a904-tf-6-transmission-alto-red-eagle-performance-master-level-2-rebuild-kit-1960-71.html

From SONNAX I already got these: rear servo piston/pin, accumulator piston, manual valve, pressure regulator valve, checkballs 1/4". I've sent torque converter to be rebuilt, just in case since I'm gonna do full rebuild.

[zidodcigalah]

UPDATE: I think I solved the mystery of aluminium chunks in pan. One of the pan bolt threads is stripped completely. Those chunks are a bit radial so I was able to match the curvature with the bolt hole. It's definitely from there, it probably ended up in pan during removal.

So far only visible damage is direct drum/ sun gear shell and a bit burnt friction discs (I re-checked and direct drum frictions are black, at least middle ones). There seems to be no huge slack between drum and sun gear shell, so I will probably keep them.

Next step would be to verify bushing wear, thrust washer wear and rear band condition. I guess washers are fine since endplay was in the middle of spec.

[Moses Ludel]

zidodcigalah...Makes sense about the aluminum and pan bolt threads if the thread material fell into the pan during removal.  The transmission case and threads are aluminum.

Pleased that you are going with a rebuild kit and Raybestos or Alto performance frictions for durability.  Smart.  Also smart that you're rebuilding this transmission based on specifications, metal in the pan, missing valve body balls and signs of wear.  This is preventive work and assurance that you saved as many hard parts as possible.  You're keeping the Jeep, it's sensible to upgrade the frictions in your build.

The shiny flex plate bolts could be a Park noise.  Without the Sonnax pressure regulator valve or full lubrication when in Park, there can be less fluid in the converter.  The crankshaft can move forward slightly when converter and pump pressure build, which could move the flex plate and bolts away from the dust cover.  In Park the crankshaft could ride slightly rearward, enough to allow the scraping and possible noise.  When you shift into gear, the converter fills, the crankshaft moves slightly forward, allowing bolt clearance at the dust cover.  Pure speculation but worth checking.

A quick answer here would be to check the crankshaft end play with a dial indicator either at the front of the crankshaft or rear/flex plate.  With a pry bar and block(s) of wood to protect parts, pry the crankshaft forward and take a measurement.  Now move the crankshaft rearward and note the amount of movement.  You're actually checking the crankshaft and thrust (main) bearing clearance.  If within specification and normal, and if you have the factory shim/spacer between the engine block and bellhousing, the issue is simply a misaligned tin dust shield.

You have a readily rebuildable transmission.  The Sonnax parts and converter rebuild are insurance and practical.  You'll notice the immediate response when shifting from Park to gears with the Sonnax parts.  I like your options in the rebuild kits, each has the front pump bushing.  The longer bushing is a tailhousing bushing for RWD (2WD) cars with a 904/999 tailhousing. This bushing would not be used in your unit.  These kits do not contain the retainer bushing and shaft bushings, which are less prone to wear.

Moses

 

[zidodcigalah]

Moses, I really appreciate all of your help and advices. In the past few years I try to be less part changer and more diagnostic, but that is not easy for people like me who don't have hands on experience. Thanks to you we were able to pinpoint possible causes of the problem.

Even though I could probably get away with existing parts (+ checkballs) this is something that will have to be done in 10-20k miles or less anyway (spec says so). No point in reinstalling it in the vehicle without rebuilding first. Same applies for converter.

I hope this thread will be useful to someone who might be dealing with an issue like this one. 

One last questions before I order parts - I checked rear band lining. If I understood well, these don't fail too often. However, mine has some black lines along the lining. Is this one salvageable or I should order new one?

[Moses Ludel]

zidodcigalah...There is some heat damage and friction slippage evident on the band.  What you look for on this band is the shape of the ribs.  Ribs should be prominent and not flattened like what you see.  The material is worn on this band.  At this stage, the ribs cannot retain fluid or provide adequate friction, which shows up as slipping or shudder during shifts.

Here is a new band from Oregon Performance Transmissions.  Note that there are distinct, raised ribs.  Sometimes a rebuilt band has wider ribs, but the ribs still have distinct height and channels.  Your band's ribs look flattened from wear.  I would replace this band (new) or have it rebuilt.  Often these rear bands are an exchange/rebuilt part:

One cause of rear band wear is poor maintenance.  Modern shops or garages, and certainly owners, have no concept of routine band adjustment or how to perform the adjustment.  Contemporary transmissions do not have band adjustments; the Chrysler RE/RH units were among the last with adjustable bands.  Bands get neglected until there is slippage or shudder during shifts.  Your 32RH transmission rebuild will last for many, many years because you are doing a thorough job and will perform the necessary maintenance.

Moses

[zidodcigalah]

Yup, I believe this trans had around 175k+ kilometers before bands were adjusted

[Moses Ludel]

That kind of neglect will do it!  Most ignore the factory recommended band adjustment intervals.  After a rebuild, I always readjust the bands after several thousand miles.  This accounts for the "shaping" of the bands and lining plus any slack that might occur.  Beyond that, the long band service intervals are okay.  As you can see, the front band, and to an extent even the rear band, have very little room for friction material wear. 

The front band in particular has surprisingly thin lining due to the need for flexibility at that band.  Even the clutch pack frictions cannot slough off much material.  An automatic transmission is nothing like a manual transmission's thick clutch disc and friction material.  The "wet clutches" in the automatic transmission rely on adequate hydraulic pressure and the right "timing" of the band applies.  The band adjustment affects that apply timing. 

When I drive our Ram/Cummins 5.9L turbodiesel powered truck, I am very aware of the upshifts, especially under load or when trailer pulling.  I do not apply heavy throttle at the shifts between gears since this is the highest wear point for the frictions and bands.  If road conditions allow, I often back off the throttle slightly to allow the shift to occur with less load applied during the shift and minimal risk of slippage. 

The safeguards that will help in your transmission are the Sonnax accumulator piston upgrade and the valve body lubrication upgrades.  I will be interested in your impressions after restoring and upgrading this transmission.  You were aware of driving quirks and symptoms, which should result in some insightful comments.

Moses

[zidodcigalah]

Still waiting for the rebuild parts, I guess because of omicron and holidays the delays are huge compared to 2 years ago.

In the meantime, I cleaned up valve body parts. I was stupid enough not to lube separator plate after cleaning it with water and degreaser. It was fine until I left the parts in the trunk for 2 nights and now I can see surface rust appeared on the separator plate. Can I just remove rust with scotchbrite or this is something to worry about? Seems like it appeared only on exposed sections where vb mates with the case (I temporary reasembled everything to prevent losing springs/screws, guess that saved the rest of the plate).

[Moses Ludel]

zidodcigalah...Vinegar or solvent with fine grade Scotchbrite should remove surface rust like this.  Fine should not damage the surface.  Unless the rust etched into the metal, the plate should be fine.  A film of ATF will keep the rust away.

I'm finding that parts orders are dragging, even with Amazon Prime.  Prime shipments can take three days to a week now.  I'm sure this is the log jam from supply chain obstacles.  This will pass when shipping normalizes.

Let us know how the plate turns out...

Moses

[zidodcigalah]

Ok so here are the parts used for a rebuild: 

 

• Alto clutches (9) with kolene steels (8), bushings/washers/gaskets/rings from kit
• Kevlar front and rear bands
• Sonnax accumulator piston (22841-04K)
• Sonnax rear servo piston (22912A)
• Sonnax rear servo piston plug (22912-01K)
• Sonnax pressure regulator valve (22771A-02K)
• Sonnax manual valve (22771-09)
• Sonnax check balls 1/4" (10000-08)

Here are a couple photos of a rebuild:



I removed all the separator plate rust with scotch brite and tried to polish it a bit with 1500 grit paper. No deep scratches present on the plate, no damage on check ball holes, checked for flatness  so it looks good. It's not really mirror polished but it looks fine ( scotchbrite did leave some fine marks but none of them can be felt with nail, I guess that is only visual).

I did couple of passes on valve body/transfer plate with 400-ish grit paper, without much pressure, just to remove any potential metal particles. Check balls are held with blue assembly goo.

 

Rear clutch assembly in progress. Checked clearances after assembly, close to min specs. No photos of front clutch assembly since I had hard time improvising with C clamps

 

Case ready to accept parts

 

I'm mostly done but have a couple of doubts:

1. Kit came with 9 clutch disks. In my 32rh, there were only 8, and ofc there is no way to install all of them. Should the pressure plates be machined so that front drum can accept 5 disks instead of 4?
2. I did notice couple of inconsistencies in FSM. I have 1995 YJ (sold as '96) and manual for '95. Valve body diagrams are inconsistent and there are some details regarding governor that I can't understand. Not sure what applies for my year?
   • Switch valve orientation seems wrong. Then I checked in 2000 TJ FSM and there its fine but throttle valve is weird. I did a research and couldn't find single picture/video with throttle valve oriented like in that photo
   • In '95 FSM they mention indexing governor body before removal since output shaft is spotfaced to accept valve, but I couldn't see anything being machined over that hole. In 2000 FSM there is no mention of that.
   • In '95 FSM they say to mark location of rear support, but on mine there is an arrow with "Pan Face" stamped on it so I guess no need to do that.
   • 
3. I was not careful enough and I damaged rear clutch piston seal during installation (guess plastic I used was too sharp..). Is this damage severe? I can't afford to wait months for parts, thinking about reinstalling old one if this one is too damaged.
    
   
    
4. I did a light test for all valves, and I couldn't see any light leaks except one on the pressure valve. It was present with both old and new(sonnax) pressure regulator valve. No damage on the old valve coating. In diagram this area is marked with dots.
   

[zidodcigalah]

Last photo is there by mistake. I haven't mentioned that I'll probably relocate vent. However, I'm unsure which location would be fine to do so? I've seen people drill hole just above the pump close to factory vent and then seal the old vent. I find this weird but maybe I'm missing something.

[Moses Ludel]

So let's go through this together, you've covered a lot of ground...I'll make comments in your post below, using red text to stand out:

11 hours ago, zidodcigalah said:

Ok so here are the parts used for a rebuild: 

 

• Alto clutches (9) with kolene steels (8), bushings/washers/gaskets/rings from kit
• Kevlar front and rear bands
• Sonnax accumulator piston (22841-04K)
• Sonnax rear servo piston (22912A)
• Sonnax rear servo piston plug (22912-01K)
• Sonnax pressure regulator valve (22771A-02K)
• Sonnax manual valve (22771-09)
• Sonnax check balls 1/4" (10000-08)

A thorough parts list.  Did you get the Sonnax "rooster comb" detent spring-and-ball kit with the stainless sleeve?  There's an optional custom drill/reamer that goes with that sleeve installation.  I addressed this in the Ram 48RE valve body work.  The kit overcomes the bore wear and detent ball sticking issue.  (I have re-themed the magazine site.  The Sonnax upgrade article is temporary offline while I adjust posts within the new theme.  You may recall that coverage.)

Here are a couple photos of a rebuild:



I removed all the separator plate rust with scotch brite and tried to polish it a bit with 1500 grit paper. No deep scratches present on the plate, no damage on check ball holes, checked for flatness  so it looks good. It's not really mirror polished but it looks fine ( scotchbrite did leave some fine marks but none of them can be felt with nail, I guess that is only visual).

This should work...

I did couple of passes on valve body/transfer plate with 400-ish grit paper, without much pressure, just to remove any potential metal particles. Check balls are held with blue assembly goo.

Nice work here.  A quick and inexpensive way to "plane" these parts is to place the 400 or finer paper on a piece of flat glass.  Use a low volatility solvent, ATF or fine oil on the paper and rub the piece circularly.  This will level/plane the piece.

 

Rear clutch assembly in progress. Checked clearances after assembly, close to min specs. No photos of front clutch assembly since I had hard time improvising with C clamps

Understand...I bought the K-D universal spring compressor years ago, it has worked on a couple dozen transmissions of various manufacture.  I paid around $80 for the tool in the mid-2000s.  Here's a different design that would work, priced at $30 currently on Amazon.  For minimal use, $30 is better:

https://www.amazon.com/Automatic-Transmission-Compressor-Removing-Installing/dp/B01GZVXX9W/ref=sr_1_6

 

Case ready to accept parts

 

I'm mostly done but have a couple of doubts:

1. Kit came with 9 clutch disks. In my 32rh, there were only 8, and ofc there is no way to install all of them. Should the pressure plates be machined so that front drum can accept 5 disks instead of 4?

Clutch disk count can often vary based on the thickness of the steels and frictions.  The stack must start and end like OEM with frictions and steels in the right positions or order.  What matters is the stack height or clearance of the assembled clutch pack.  This needs to match the OEM specification.  Use the FSM to determine the correct installed clearance with the clutch pack assembled.

1. I did notice couple of inconsistencies in FSM. I have 1995 YJ (sold as '96) and manual for '95. Valve body diagrams are inconsistent and there are some details regarding governor that I can't understand. Not sure what applies for my year?
   • Switch valve orientation seems wrong. Then I checked in 2000 TJ FSM and there its fine but throttle valve is weird. I did a research and couldn't find single picture/video with throttle valve oriented like in that photo
   • In '95 FSM they mention indexing governor body before removal since output shaft is spotfaced to accept valve, but I couldn't see anything being machined over that hole. In 2000 FSM there is no mention of that.
   • In '95 FSM they say to mark location of rear support, but on mine there is an arrow with "Pan Face" stamped on it so I guess no need to do that.  I have 1994 and 1998 FSMs.  If helpful, I can capture this image from 1998.  Let me know if you need it.
   •  
2. • 
3. I was not careful enough and I damaged rear clutch piston seal during installation (guess plastic I used was too sharp..). Is this damage severe? I can't afford to wait months for parts, thinking about reinstalling old one if this one is too damaged.
    
4. Damage looks minor from the photo.  However, the real test is how much the rubber will compress and flatten this section when installed.  If compressed enough, it will seal...Also, the seal needs to stay together;  the nick must be surface only and not lead to a rupture of the seal.  The good news is that the rubber is new and still pliant...You can check the function of the seal with a compressed air check when the clutch is together on the bench.  Check for a leak with soapy spray while applying air pressure.
    
5. I did a light test for all valves, and I couldn't see any light leaks except one on the pressure valve. It was present with both old and new(sonnax) pressure regulator valve. No damage on the old valve coating. In diagram this area is marked with dots.
6. Minor bleed-off would not be an issue.  More wear would allow a pressure bleed-off.  If the bleed is minor enough not to move valves or reduce fluid pressure substantially, you are okay.  Despite its thin viscosity, ATF has some sealing ability if the wear is minor. 
7. 

 

[Moses Ludel]

zidodcigalah...Regarding the vent relocation, you have a need to do this?  What is the trend and why?

Moses

[zidodcigalah]

Thanks you Moses. I remember that article but I haven't ordered that comb upgrade, somehow I missed it when I placed orders. As for the clutch spring compressor, I couldn't ship it from USA since I already maxed out the shipment weight, so I thought to either fabricate something or try with clamps

I did check front/rear clutch clearances, they are within specs from FSM (close to min specs, unfortunately didn't check it while they were dry). I saw that most kits for a904 came with 7 steels and 8 clutch disks - even Alto official catalogue lists same numbers. I thought that these front clutches are thinner than OEM and that is why they provided one extra friction/steel for front drum but it looks like that is not the case.

As for the kickdown valve and switch valve orientation - I checked the hydraulic diagrams and it seems that switch valve from first photo and kickdown valve from second are not oriented properly. Guess it's an error in FSM. 

Regarding vent relocation - I found a bunch of information online that getting stuck in deep water could cause water to enter thru vent hole in transmission. I did get stuck once but didn't find any traces of water in the transmission later on, but if relocation could prevent future damage I'd do it. Here is one of the posts: https://www.jeepforum.com/threads/relocating-vent-on-32rh-3-speed-auto.462033/

This location looks to me like it would do more harm than good, but again I might be missing something.

[Moses Ludel]

zidodcigalah...Improvising a clutch compressor worked...Thinner disks do call for a higher count.  The only issue here is the orientation of the disks to assure the right function and confirming the right clearance.  Yes, you would need to allow slightly for frictions with fluid saturation versus dry.

Sounds like you figured out the kickdown valve and switch orientation?  FSMs sometimes generalize and can also import data and illustrations from various model years. 

Looked at the forum link for the vent relocation.  Some questions:  Where does the OE pump vent route into the transmission?  What exactly gets "vented" here?  Is the main case cavity the area vented?  Does the pump vent feed directly into the cavity?  Your aim is to replicate the function of the OEM vent.  Be sure that transmission fluid will not enter the vent hose under pressure when the gear set is slinging ATF and pressurizing the cavity.

When attempting to align a hole without causing havoc, it would be best to index the hole with the front pump out of the case.  (You'd want to do this anyway to enable a full vacuuming and cleanup of drill debris.)  You can measure the depth of the pump to be sure of the installed location.

The hole needs to serve the same function as the OEM vent.  Routing the vent hose way up on the firewall has been my traditional approach with transfer case or transmission venting.  That end is easy with a one-way vent valve, an OEM plastic type works as long as debris cannot enter the hose and transmission.  My main concern here is the new hole location in the transmission case.

Another approach altogether is shown in the illustration below.  This picture is courtesy of the Jeep Wrangler TJ forum.  If there is sufficient clearance between the elbow fitting, hose and the torque converter, you would be using the OEM vent source.  That would eliminate guesswork about proper venting and pressurized fluid pumping out of the transmission.  Presumably, this installer tapped the vent hole with an 1/8" NPT tap although the need for this much sealant is puzzling.  A film of high temp Teflon pipe sealant on the threads (only) would work if the pump housing is tapped properly.  I like the tube and routing away from the torque converter.  Clearance to the converter would need to be verified.  Make sure the elbow will not interfere with the converter in position.

There is a similar approach to this one at the forum:  https://wranglertjforum.com/threads/vent-relocation-32rh-auto-1999-tj.51349/.  Check out the July 9, 2021 reply.  This installer shares my concern and comments about fluid pumping out the vent when venting from the top of the transmission case.  His tube and bracket are innovative, the tab prevents the tube from dislodging.  Sealing the tube at the vent hole would require some attention, a semi-press fit or hard (high temp) silver soldering could help.  (This is called soldering but is actually a brazing process at the low end of the brazing temp scale, similar to joining air conditioning fittings, etc.)  What I like about venting directly from the existing front pump vent hole is that this is the OEM vent source.  There is a reason for venting here.

Worth noting, I see photos of the front pump vent hole being welded shut with a top case vent conversion.  The pump vent could still allow water intake if left in place and open at the converter housing.  Drilling-and-tapping for an 1/8" allen/hex head (flush mount) pipe plug with thread sealant might be better to avoid risk of pump housing warpage.  Again, I lean toward using an elbow and a tube right out of the OEM pump vent hole if there is enough converter clearance. 

Moses

[zidodcigalah]

Its been a long time but I wanted to provide an update to this, in case someone else is on a same journey. I gave up relocating vent hole because I was in a rush and didn't want to drill thru housing since everything was already installed.

After three months of test driving I think I can call this a success. No issues at all, no more rattling noise (there is some rattling present in PARK but it's not as loud as before). I still have to properly adjust throttle/shift linkage since there is some slack there but thats mostly it.

I spent a lot of time revisiting already done work and was lucky enough that I catched some of mistakes I did during reassembly. Problem is there are some parts that you can reinstall both ways and if you don't do this often and don't have FSM or photos from disassembly its gonna be a problem. Here are some of the items where I'd advise extra care: 

1. Governor housing indexing - make sure to remember relation between gov. housing and output shaft. Also, keep track of governor weights, on my model I could install governor weight 2 ways. Manual mentions spotfaced output shaft but mine was not.
2. Kickdown valve
3. Output shaft support - there are 6 ways to install it but only one is correct
4. Sprag - has one non-threaded hole that aligns with housing hole
5. Pump gears - on '94/'95 model there is chamfered side of the inner gear, its not symmetrical
6. Fiber thrust washer between direct drum and stator
7. Lip seals - they are not like rings, they go only one way
8. Snap rings on drums - keep track which one goes where because not all are flat and it's easy to mix them

I also realized some things I was unaware about A904. I was always wondering why I can't do part-throttle downshift to 2nd if going above 65kmh (40mph). Now I realize there is limit valve in valve body that prevents part throttle downshift. Also, at some point (I believe '70s) they added 3-2 part throttle downshift module but there is no 2-1 part throttle downshift. Trans will downshift only if vehicle speed is low enough (so that gov pressure is low) or on full throttle kickdown. I always thought this is an issue with my transmission, because with stock gearing and 33" tires rpms are low and you feel undergeared so you'd expect transmission to downshift.

[Moses Ludel]

zidodcigalah...Always great to see your posts, and this one especially.  First off, you should be very pleased with the "success story" around this A904 build.  Now tested enough to tell, the transmission has obviously been built correctly.

Your candid sharing of the "rabbit holes"  and trouble areas in this build are very helpful to others.  You likely saved first-time builders a lot of headache and have steered them toward the details that need close attention...Thanks for taking the time to do this.

One approach I take with transmissions, especially those that have not been disassembled before, is to note the parts fit-up imprints during disassembly.  (This must be done before running the parts through a pressure washer or cleaning them.)  You can see the relationship of parts and their orientation.  On parts with peculiar alignment, marking the castings or pieces with a light pin punch mark can help.  This should be done away from precision or machined mating surfaces and without leaving punch mark material that can slough off...Another approach, which you describe, would be taking photos during teardown to use for a parts orientation/reference during reassembly.

Your close attention to chamfered edges, seal direction(s) and other concerns is why you had success with the build.  Thanks much for sharing your experience.  Many get discouraged on their first automatic transmission build and never do another one.  You persevered, looked for possible pitfalls, and ultimately built a reliable transmission.  You also discovered the built-in shift quirks and details around the late A904 downshifts.  This helps you distinguish "normal" shift behavior from trouble.

You're up the learning curve on automatic transmissions.  The good news is a successful build and upgrade of your A904.  More importantly, you have familiarized yourself with the A904 transmission build (plus the 30RH/32RH units) and now know way more about automatic transmission rebuilding!

Looking forward to your posts...

Moses