Jeep YJ 2.5 Wrangler - Rebuilding Dana 35 Axle

[Sabueso]

Hi All,

I've started this new topic as a result of my last nightmare, I mean, topic.  Due to budget limits I have purchased a used Differential for the dana 35 and am going back to my regular size tires.  You can see in the link below why this all came about.  I've never done this repair but I have done a lot of DIY on my Jeep with good success.  I'm looking into youtube and the forum for suggestions plus Moses is here with professional advice.  

I plan on starting tomorrow, just waiting on other parts.  Feel free to add suggestions.  Thanks.

[Moses Ludel]

For those setting up a Dana 35, read my February 26th reply at our exchange.  I get into some of the critical Dana 35 concerns, especially the pinion bearing preload and using care when torquing the pinion nut with a new crush sleeve:

Moses

[Sabueso]

 

Sorry for being so slow but life happens.  Had to tend to priorities and the Jeep was left for last.

 

So I studied a lot of ring & pinion documents, videos and I got a copy of YJ factory service manual on-line.  Hard to find but thanks to the Youtube channel Redneck Garage you can download it here:

https://goo.gl/ci2Zt5

 

To me its practically rocket science.  But if you have time and take it slow it is definately learnable and doable.  As Moses points out the crush sleeve is very important (I ordered 2).  I bought the following used parts:

 

1 Complete Carrier with ring, pinion, bearings, c-clips and shims.

 

I bought new parts too:

 1. Seal

 2. Outer bearing with racer

 3. Shim kit for pinion

 4. (2) crush sleeves

 5. Pattern paint for the ring

 6. Dial indicator tool to measure backlash

 

With a lot of reading and the Service Manual I learned you have to note the new pinion measurement and old pinion measurement (these are explained well in the manual).  Basically these are markings that are written by hand on the pinion.  In my example my old pinion was a +1 while the new pinion was set at 0.  The book provides the calculation and a table that explains how much shimming you have to add or subtract to the pinion.

 

regarding pre-load I was able to obtain 36 inch pounds after crushing the sleeve.  Which takes a lot of strength if you're at home and there's not a lot of room under the Jeep.  It was on jack stands but it was still limiting to get under and put strength into torking.  A shop with a vehicle lift would be a lot more comfortable.

 

I did not have an expander for the differential pumpkin so getting the carrier in needed patience and my rubber malot.  I was lucky that I did not need to shim for good backlash.  

 

Previous to all this I cleaned the empty differential case very well with Brake Cleaner fluid.  Once I got all parts in and torked I tried to obtain a contact pattern.  The first one was not good so I started over using a new crush sleeve.  The second time I believe I was lucky.  Everything fell into place.  I actually had to remove shims from the pinion to back it farther away from the ring for a more acceptable pattern.  

 

Regarding patterns - you need to know the driver side of the ring teeth and the coast side.  The driver side is the convex shape of the tooth while the coast is concave. You should also study where the toe and heel are on the ring.  An optimal pattern is centered between the toe and heel and not to high or low.  In my research I did find different opinions from reliable sites where this was not always the case.  Some factor in used/worn ring and pinions (such as mine) and these produce different patterns which are also acceptable.

 

After assembly and adding gear oil I left the Jeep on the jack stands and started it up.  I put in first and went up to 2000rpm to see if I could hear noises or vibrations.  So far so good.  I then took it for a spin doing slow speeds and feeling the ride.  After 4.5 miles I can say it felt pretty good.  So far I've done 67 miles of test driving.  When I tried the highway I felt vibration over 50mph.  But I remembered that during the suspension lift I had adjust the driveshaft angles.  I had brought down the tranny skid plate using some shims.  So I removed about .5 inch from that and tested the highway speed up to 65mph (No vibrations!).

 

If all is well after maybe 300 miles or so I'm going to open up the differential to look at the gears to make sure things are still good.

 

[Moses Ludel]

Sabueso...Glad you shared all of your work with others!  Below are a few comments in red to add some details:

1 hour ago, Sabueso said:

To me its practically rocket science.  But if you have time and take it slow it is definately learnable and doable.  As Moses points out the crush sleeve is very important (I ordered 2).  I bought the following used parts:

 

1 Complete Carrier with ring, pinion, bearings, c-clips and shims.

 

I bought new parts too:

 1. Seal

 2. Outer bearing with racer

 3. Shim kit for pinion

 4. (2) crush sleeves

 5. Pattern paint for the ring

 6. Dial indicator tool to measure backlash

 

With a lot of reading and the Service Manual I learned you have to note the new pinion measurement and old pinion measurement (these are explained well in the manual).  Basically these are markings that are written by hand on the pinion.  In my example my old pinion was a +1 while the new pinion was set at 0.  The book provides the calculation and a table that explains how much shimming you have to add or subtract to the pinion.

 

Glad you used the traditional FSM method/chart for quickly setting pinion depth.  There are four things to consider when setting up a Dana 35 rear axle:  1) pinion depth, 2) pinion bearing preload, 3) ring gear bearing preload and 4) ring gear backlash.  The first and foremost concern is the pinion depth, once correct everything else falls into place.  This is especially important on a used set of gears and carrier.

 

regarding pre-load I was able to obtain 36 inch pounds after crushing the sleeve.  Which takes a lot of strength if you're at home and there's not a lot of room under the Jeep.  It was on jack stands but it was still limiting to get under and put strength into torking.  A shop with a vehicle lift would be a lot more comfortable.

 

Is this the pinion shaft rotational reading with new bearings?  36 in-lbs would be somewhat tight for used/original bearings but acceptable for new bearings. 

 

I did not have an expander for the differential pumpkin so getting the carrier in needed patience and my rubber malot.  I was lucky that I did not need to shim for good backlash.

 

Use of a rawhide mallet or plastic sand filled hammer while cocking the bearing cups during installation (without damaging the bearing cages) is the time-honored Spicer/Dana approach...The spreader was not always available.  If you use a housing spreader, 0.015" spread of the case is plenty!  Any more than this will distort the axle housing/case and leave it stretched.  

 

Previous to all this I cleaned the empty differential case very well with Brake Cleaner fluid.  Once I got all parts in and torked I tried to obtain a contact pattern.  The first one was not good so I started over using a new crush sleeve.  The second time I believe I was lucky.  Everything fell into place.  I actually had to remove shims from the pinion to back it farther away from the ring for a more acceptable pattern.

 

That can happen, even with the chart and Dana +/- approach.  The final and most essential test is ring gear backlash and the correct tooth contact pattern.  When testing the tooth contact pattern with paste, I like to load the pinion shaft by wrapping a hefty rag around the pinion nose/flange neck; tighten the rag like a tourniquet, placing a load on the shaft.  Rotate the ring gear at its bolts with a box end wrench; the loaded pinion makes a more distinct tooth impression pattern in the paint. 

 

Regarding patterns - you need to know the driver side of the ring teeth and the coast side.  The driver side is the convex shape of the tooth while the coast is concave. You should also study where the toe and heel are on the ring.  An optimal pattern is centered between the toe and heel and not to high or low.  In my research I did find different opinions from reliable sites where this was not always the case.  Some factor in used/worn ring and pinions (such as mine) and these produce different patterns which are also acceptable.

 

Glad you took the "used" gear pattern into consideration.  You were unable to observe the original pattern on these used ring and pinion gears.  Your final pattern needed to match gears with a normal (after break-in) pattern.  Your ring gear backlash should be 0.005"-0.008".  I like 0.006" when setting up a Dana 35, but more important is the tooth contact pattern.

 

After assembly and adding gear oil I left the Jeep on the jack stands and started it up.  I put in first and went up to 2000rpm to see if I could hear noises or vibrations.  So far so good.  I then took it for a spin doing slow speeds and feeling the ride.  After 4.5 miles I can say it felt pretty good.  So far I've done 67 miles of test driving.  When I tried the highway I felt vibration over 50mph.  But I remembered that during the suspension lift I had adjust the driveshaft angles.  I had brought down the tranny skid plate using some shims.  So I removed about .5 inch from that and tested the highway speed up to 65mph (No vibrations!).

 

No vibration and no noise on coast or drive/acceleration is the goal!

 

If all is well after maybe 300 miles or so I'm going to open up the differential to look at the gears to make sure things are still good.

 

Couldn't hurt...Changing the lube makes sense, too.  At the very least, I would filter the lube by flowing it through clean mesh metal cloth/wire, something like 70 or 80 mesh for gear lube.  (I use 100 mesh for ATF.)  If this is not available, consider flowing the lube through clean, lint-free cloth and inspect for debris...Wipe out the housing and look for any sign of metal debris.  Check gear backlash and push on the pinion (firmly) sideways at the pinion U-joint flange to be sure the bearing preload feels right.  You can't test pinion preload once the driveshaft, axle shafts, wheels and tires have been installed.

 

Moses

 

 

[Sabueso]

Thanks Moses for the tips and votes of confidence.  So far so good after 95 miles.  I can't do more due to the fuel problem I'm having which I described in my other post (see below):

I followed some of the posts here regarding troubleshooting, specifically the very long post who bought the fuel pressure regulator from ebay.  I still have the same issue but follow me there as I'm going to post more things I've done which have not helped.

[Moses Ludel]

Looking forward to your update on the fuel problem...We've covered every angle of 2.5L troubleshooting, you have much info available.  Let us know what you find...