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Moses,

I am starting the Twin Stick Dana 300 rebuild to address the jumping out on down grades issue. This unit had major work about 16K miles ago when a 4:1 gear kit was installed by a pervious owner. The Odometer now has 282K miles and most likely is was a California commuter Jeep in its early days (266K miles 1985 - 2003). This may be an interesting journey.

First look don't seem too bad.

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Clocking Ring and Input Shaft.

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Clocking Ring Gasket was not salvageable. Not real sure what its function was as it is not a water or oil seal.

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Input Bearing Unit Removed.

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Even though I plan on installing a master kit, the input gear/bearing assembly looks and feels so good, I am reluctant to take it apart. Moses, you may have some input on that.

Now for the bad news.

The front shift fork was binding on the shift rail so tight that it took a couple of hours to separate the two. Once I finally got them apart, my nerves were completely shot and set them both to the side to be inspected maybe tomorrow.

Centered in this picture is the rear output gear. On the right half of the rear output gear is the High Range side of the gear showing quite a bit of wear. If I were guessing, this gear is the original with 282K miles. To the right you can see the input gear that is in good shape. Not shown, is the Low Range gear that would normally be to the left in the picture, and it looks as good as the input gear.

The sliding collars are most likely original as well. However the wear was not as pronounced as the rear output gear, but still more wear than I would like. Also the collars had been swapped around by the previous builder for the best fit.

Even though this Rear Output Gear was not causing trouble, I am not comfortable with it and have ordered a replacement along with 2 shift collars.

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Had my wife steading the case while I was pressing out the bearings. One of them let go with a good pop and she was sure we had broke something. LOL.

Moses, you might want to jump in with this popping out issue. I will pay very close attention during installation to linkage binding.

I am already planning on installing the stiffer JB Conversions detent springs. New shift collars can't hurt. Is there any thing about the shift rails you can thing think of?

William

 

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This project will be right up your alley, William...There's a lot to check in the way of bearing clearances, gear clearances, gear and shaft fit, end plays and the integrity of the aftermarket 4:1 gear kit parts.  Do you know who manufactured or at least marketed the 4:1 kit?

I'm already wary of the gear tooth wear pattern.  First, this looks like minimal tooth engagement if actually "in gear".  Let's see where this leads...

Moses

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Moses,

I was able to match the numbers on my 4:1 gears to the ones on the TeraFlex installation video. Not sure who makes them for Teraflex.

The rear shift fork binding on the rail appears to be due to a burr on the fork originating from the set screw thread area.

Spent most of the day cleaning all the housing parts except for the input bearing assembly and clocking ring.

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Rear Output Shaft should be here on Tuesday. The Shift Collars were backordered.

William

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Moses,

I now need to make a decision about replacing the input bearing and seal or not. The current one is very smooth and does not leak.

I have the Advance Adapters Clocking Ring that comes with adapter, input shaft, gasket, and sealed bearing.

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I purchased the Advanced Adapters Dana 300 Master Rebuild Kit that comes with an open bearing.

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The existing Input Assembly uses a what appears to be a OE style Oil Seal, on the outboard side of the shaft assembly. If you back up a few pictures, you can see the Input Assembly Oil Seal in the background on the bench behind the case. Is there a way for oil to pass by this sealed bearing to lubricate the oil seal? Confused about whether to leave as is or to install new bearing and seal. 

William

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William...As usual, I like your thoroughness and attention to detail, the photos help...Did your Dana 300 come with the Advance Adapters clocking ring, input shaft and a sealed bearing?  Or did you just now order a clocking ring, adapter shaft and sealed bearing from Advance Adapters?  The AA master rebuild kit for a Dana 300 comes with an open bearing, right?  The AA clocking ring kit always comes with a sealed bearing?

Your concern about the OE front seal is apt.  If the seal runs dry, it will damage the seal lip or wear a groove in the adapter shaft's sealing surface.  Does your input bearing retainer have a return oil passage for oil to get from the cavity between the seal and the front side of the bearing, then back into the transfer case?  If so, would this opening provide enough back flow oil to sling up into the cavity and lube the seal?  

The quality of the sealed bearing is beyond concern, I know Advance Adapters uses high quality bearings.  There are arguments both ways about the use of a sealed bearing, and yes, it does block oil flow through the bearing.    The only possible way oil can get past a fully sealed bearing (one where both sides have seals with permanent grease inside) would be minute seepage between the bearing's outer surface and the bearing bore of the retainer.  This is very unlikely and minimal, since the bearing is a near interference fit in the bearing retainer bore!

There must be an Advance Adapters' motive for the double-side sealed bearing.  I've built many 4x4 magazine and book vehicles and have always used Advance Adapters components.  Generally, there are transfer case adapter to transmission applications where spline wear on dry adapter spud shafts can be an issue, but that's not the situation here.  There are also instances where there is a risk of oil seepage into the space between the transmission and transfer case, and that could be a possibility here.  The clocking ring is outboard of the case and surrounds the OE bearing retainer, so that's not an issue.  This has to be a judgment call around the lifespan of the bearing or perhaps the risk of potential oil leakage through the front seal when using an OE type open bearing.

On the Dana 300, there is normally good oil flow into the front bearing when open-sided.  Oil can return through the passages and does not pool in the retainer unless there is 1) a clogged return passage to the case or 2)  the vehicle is on a very steep down grade and oil is pouring through the bearing and also the return passage into the oil seal cavity.  Perhaps Advance Adapters has found a superior bearing is needed with the longer adapter nose and splines, and the only bearing type that meets the requirement is double-sealed.  Or, they may simply not want customer issues with bearings, and there may be a history of retainer seal leaks getting falsely blamed on the clocking adapter kit.

Not sure about the motive for the sealed bearing.  I am curious why your transfer case has a clocking ring, though.  Did the 1985 T-5 require an adapter plate between the tailhousing and the Dana 300?  Or are you clocking the transfer case intentionally to reduce the front driveshaft slope or, oppositely, to tuck the transfer case further up into the chassis?

Moses 

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Moses,

My Dana 300 came with a AA Clocking Kit to increase ground clearance. The AA Dana 300 Master Kit comes with an open bearing. According to the documentation that I have found all new AA Dana 300 Clocking Kits come with sealed bearings.

I inspected the input bearing housing and did not see a oil bypass cavity. At this point, I must rely on AA recommendations and go with what is supplied for the a Dana 300 with a Clocking Kit. It would be foolish for me to assume that I am smarter than AA engineers, especially in light that most likely it costs more to supply a sealed bearing. The good thing is, my sealed Input Bearing and Shaft are in great shape.

Pressing in the new bearing races. Even using cold races, they go down really hard. Make sure you address any tool marks on the race seats before you begin. Use plenty of lube and make absolutely sure to keep the race straight as it goes down.

I also threaded the tail housing to 1/8" pipe thread for a new vent tube.

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Installed the new JB Conversions Detent Springs. The springs are the same length and longer and stiffer than OE springs. OE springs are different lengths. The kit comes with two springs and one 5/16" ball and absolutely no documentation. I can only assume that the 5/16" ball goes in the front shift rail bore as it is not as deep. With the OE 3/8" ball and JB spring in the rear shift rail bore and the 5/16" ball and JB spring in the front shift rail bore, they are sitting at the same height. These springs are real stiff and took several tries to get them compressed enough to slide in the rails, especially on the front rail with the 5/16" ball.

Also installed two new O-rings on the bore plugs, not supplied in the Master Kit. Notice the large cutout in the rear shift rail for the larger 4:1 gears.

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William

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William...Nice work and I understand your decision to keep with the AA double-side sealed bearing.  

I would place quality chassis grease between the front seal lips of the retainer.  That should resolve the bulk of the friction issue between the seal and seal surface on the adapter.  The correct grease should stay in there for a long time.  I do this as a matter of course with double-lip seals on OE applications.

When I press bearings, races or bushings into a metal bore, and aluminum is tricky as we know, I use a film of grease on the bore or apply Sunnen B200L.  Sunnen lube is popular with machine shops and available through outlets like Goodson:  https://www.goodson.com/Sunnen-Press-Fit-Lubricant/.  For an interference fit, this lube protects against galling and seizure, especially with sensitive bronze bushings.  The 200L brush applicator variety goes a very long way, you need only a thin film to work.

Moses 

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Moses,

Excellent point about supplying grease for the Input Seal. I had already considered that.

I find, for parts stuffing purposes, a simplified exploded parts diagram along with associated descriptions all on one page to be very helpful during the assembly stage of a rebuild.

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Works even better for us older guys if you can print on 11 x 17 paper.

William

 

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Useful reference diagram, William...Grease on a double-lip seal's recess is a time honored way to make sure the seal will not become damaged before oil reaches it...Old school, and I qualify...

Moses

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Moses,

FYI, reached out to AA on the issue of the Sealed Input Bearing and got this reply.

"We provide the sealed bearing for extra insurance against fluid transfer (common when using automatics) Since you are using a T5 and as long as the input seal is replaced in the bearing retainer you can use either the open or sealed bearing."

William

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Okay...That will have to do.  Not clear how the two fluids would mix:  The Dana 300 input is fully sealed from the transmission, and the adapter shaft's splined input end is a blind bore that does not allow transmission fluid to transfer into the transfer case, right?  Apparently, either bearing works, though.  The choice is yours, are you still going with the sealed bearing already in place?

On that note, you need to lube these splines and the transmission output splines to reduce friction and wear.  Even though these splines align and do not float end wise, there is the torque friction between the splines that needs attention.  You have the rear seal on the T-5 that keeps transmission lube from reaching this point.  Correct?

Moses

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Moses,

Still struggling with the decision to use the sealed bearing or not. The decision parameters center around the fact the sealed bearing assembly is in great shape with about 16K miles, I do not have a pair of snap ring pliers large enough to remove the gear retainer, and I do not have a replacement snap ring. For now the project is in neutral waiting the Shift Collars. Sort of leaning toward reusing the old complete sealed bearing/retainer assembly.

Yes my T-5 is sealed as well as the Dana 300. The T-5 rear coupling flange has a "weep" hole to allow fluids leaking from either the T-5 or the Dana 300 to escape.

Excellent point about lubing the shaft splines.

William

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Moses,

Back on the Project. Looks like the shift collars are now out of production and mostly out of stock. I was only able to obtain one new one. The good thing is, I really only needed one. Put best one of the two used ones that had very very little wear on the front shaft.

Found the Rear Shift Fork Pads installed backwards by previous builder.

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Removing the old Front Shaft Bearing. Removed Bearing Cage and Rollers first.

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Installing first Front Shaft Bearing. Used old Bearing Inner Race next to new Bearing during the install process.

Make sure you double check the correct Bearing placement as they are very close in size.

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Installing the second Front Shaft Bearing. Don't worry, I straighten it up before putting pressure to it. Had to balance the case with one hand and hold the camera with the other.

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Ready to install the Front Housing. Since I elected not to use the paper gasket, I needed to add 0.012" to the front shaft preload shim pack.

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Front Shaft assembled.

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William

Edited by William H
Updated Pictures

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Nice progress here, William!  I like your consideration for items like the shim pack adjustment when you eliminated the cut paper gasket.  These gaskets have a notorious history of pounding out, shrinking, stretching and leaking.  However, we do need to respect the clearances that gaskets create.  With RTV sealant, you have a virtual "interference fit" between these parts that will not waver in service.

Note:  The most troublesome gasket on the early Spicer Model 18 transfer case was between the transmission and transfer case.  This paper gasket took the torque, rocking, fore-and-aft thrust and every other kind of distortion until eventually it leaked...on every Willys-Kaiser Jeep 4x4 I've ever seen!  Often, the bolts and lock washers would loosen from the cut gasket getting pounded.

In the modern era of RTV sealant, OEMs have eliminated paper cut gaskets.  You did that here, knowing Dana expected a clearance where the gasket resided.  You compensated for that in your shim pack adjustment.  I also like your prudent, strategic use of RTV sealant.  This will flatten and spread over the areas that require sealing.  

You're building a "blueprinted" and tightly sealed Dana 300 that should run for a couple hundred thousand miles or more with the right lubricant.  The Dana 300 is considered the best transfer case ever built for a light Jeep utility 4x4 model.  You're assuring that level of service.

Fantastic photos once more...Thanks!

Moses

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Moses,

Input/Rear stack installed.

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Intermediate Gear Installed.

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Back in neutral waiting on delivery of rear shaft shim pack next week. Not supplied in the AA Master Kit.

William

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Moses,

During initial teardown, there was a gasket between the transmission and the transfer case. Since both units are oil sealed and there being a excess oil drainage channel in the cavity between the units, I don't understand the function of this gasket. Maybe a "Shock Absorber" ??

This gasket is intact and reusable if needed. Average thickness is 0.028" and made of heavy paper.

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Rear view of the Transmission.

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Front view of the Transfer Case.

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Unless someone can shed some light here, I am leaning toward leaving it out.

William

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William...If the transmission's output shaft has plenty of depth clearance in the transfer case input spline cavity (without the gasket), removing the gasket would be an option.  This is not a shim or selective fit spacer.  From the gasket photo, I can't tell whether the gasket allows weepage from the drainage channel or not.  There cannot be much weep in any case.  More likely, this may be a pressure relief channel.

If you decide to eliminate the gasket and use RTV sealant in its place, allow the channel to perform its intended function.  One way to accomplish this is to apply your RTV sealant bead to the flange and place a drill bit or small jewelers screwdriver in the channel.  Bolt the case to the flange and allow the sealant to cure, then remove the bit or screwdriver.  This will leave a weep hole and pressure relief void...You may have an even more creative approach, but you get the idea.

Footnote: Given the many holes in the Advance Adapters clocking ring, the gasket would have Swiss cheese impressions.  Another reason to eliminate it?

Moses

 

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Moses,

The good news is a couple months ago I found a new heavy duty yoke wrench on ebay cheaper than common light duty models that reviews indicated they were subject to bending.

The bad news is that ad indicated it would fit a 1310 series yoke. However the hole spacing was way too large.

With careful measurements, I used a CAD program to create a precision template to drill four new holes. Fits a 1310 Yoke now like a glove. The wrench ring was so large, I needed to remove about 1/4" of metal from the upper end of the ring (right side in the picture) in order the clear the shifter housing when tightening the front Yoke.

Torqued the Yokes to 130 Ft/Lbs.

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With access cover and spedo gear installed the Transfer Case is now waiting to be reconnected to the Transmission.

William

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William, my D300 is sitting on the bench right now.  Since you wouldn't cough up yours with the 4:1 gears, I had to buy a set for myself :)

Funny that you had to wait on the output shaft shim kit; I also needed that.  I hope to get my new gears installed this weekend.  My Jeep club has a Jeep show at a local dealership on the 18th and our Spring Run is 1 April.  Lots of work to do before then.  Good luck with your reinstallation.

Case

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Case,

You are going to love the 4:1 Gearset, especially when you need to start from steep incline and using the "No Clutch Starter In-Gear" method. If you don't already have one, you might want to consider adding a hand throttle at some point. They are so nice, as I started using one in 1978 on my CJ5. Really helps when crawling up steep old rocky inclines by maintain constant wheel torque where bouncing action of the Jeep makes it hard to keep your foot steady on the pedal. Mine is mounted on the transmission gear shift and is a easy reach. Just set it to a fast idle and you will have enough engine torque to absorb ledges and rocks. Even if you break traction, many times I let it grind slowly just for a couple of seconds and it will find a bite again once the Jeep shifts around a bit. With your 4:1 Gearset, you will enjoy making sure that everyone behind you on those long rocky inclines has a hard time maintaining their interval. Ha Ha! 

Since I have been offline for a couple of weeks, I am now in somewhat of a time crunch myself. Not as serious as yours, however. Grass is coming on sooner than usual this year and with all the disassociated Jeep parts laying around, It would be a major operation to get the mower out. I've about 1 1/2 weeks before this becomes critical.

Good luck with your Show and Spring Run. Keep us posted.

William

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William,

I do indeed have a hand throttle.  I used to be a bike mechanic, so  I always have a box of spare parts lying around.  I bought a Teflon coated brake cable and had everything else I needed on hand.  With the 4.0 conversion, there is even an extra hole on the throttle cable plate.  Best $10 upgrade I ever did.  I really don't think I could have done some of the trails I have completed without the hand throttle. 

Good luck beating the grass.

Case

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Lovin' that yoke wrench, William!  You could do a 200-300 plus lb-ft axle yoke nut without a hitch, even easier for your Dana 300 yokes at 130 lb-ft.  

Nice tooling for doing the job right...Your M.O.

Moses

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Moses,

Wednesday was the 50 mile highway "Shake down". Performed well through out the test. Shifting was smooth and easy with positive detent. I tested it on a very steep gravel road incline that had proved a problem to keep it in 2 wheel low in the past. Passed with flying colors.

Upon inspection back in the stable, I discovered there was a major oil leak from the rear seal.

Further Inspection results:

Yoke splines were high and dry.

Zero end play in the rear shaft.

With driveshaft disconnected, Yoke and rear shaft runs true.

When installing the rear seal, I added a little RTV to the outer edge of the seal. It had several weeks to cure with the ambient temperature ranging from 50 to 60 degrees. When I went to remove it, popped out very easy with the first pull.

Inspection under a magnifying light revealed no defects.

Unable to determine if leak was from the inner or outer portion of the seal.

I installed a new seal on Friday with Loctite Anaerobic sealer on the outside edge. Let it cure until this morning and ran it for 30 miles @ 25 MPH without the driveshaft and it did not leak a drop. Will road test again once the weather clears and the roads dry off.

William

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Sounds like you nailed it, William!  Time to drive the Jeep and keep an eye on things for a bit.  Very pleased with your shifting results and the shift detent "feel".  Transfer case working well, too...Nice work!

Moses

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