75 Cj5 Rear Axle Rebuild

I am currently doing a frame off on my 75 cj5, I pulled the rear Dana 44 apart and noticed that this was not the first time someone had been into it.

I noticed that the inner pinion bearing had no slinger or locating shim underneath it although the pinion head is marked with a +2, the other thing I found was the pinion had no crush sleeve on it just shims in front of the outer bearing for preload.

I'm not terribly worried about the lack of locating shim but is the use of shims for preload typical of this era of jeep Dana 44?

 

No crush sleeve on that Dana 44.

 

Thanks for the heads up

 

D 44 has no slinger behind the pinion head but the D 30 has a big one.
Normally you'll see about .0025" shims under the inner pinion cup.
And about .0065" preload shims plus a slinger at the input seal.

 

Mine has no shim behind the inner pinion bearing or behind the pinion cup, and .048 preload shims.

I guess since I'm not changing the gearing I'll put it back in the way I found it and the pattern will reveal whether or not the last guy knew what he was doing.

 

Dana 44 should not have anything under the pinion head except the bearing.
Simply pull/press off the old bearing and install a new # 31594.
The D-44 pinion bearing seats direct up behind the pinion head.

No shims under the # 31520 pinion cup is unlikely yet it is possible.
I have a rare Dana 25 axle assembly that required no pinion depth shims.
Like I say .025 pinion cup shims will be the average.
.048 preload shim pack is less than the .065 average yet readily possible.
The main thing with setting the preload is so the pinion has zero slop or end play.
Very slight binding after rotating it several times is ideal.
You rotate it several times to fully seat and center the cup / bearing.

I agree it sure seems like somebody has messed around in there.

The first thing you need to do is to approximate the correct pinion depth.
That's mandatory.
More about that later.

Question: Have you or do you need to pull the # 25590 differential case bearings ?

 

I haven't pulled the carrier bearings yet, but I have new bearings and races for it.

Where did you get the part numbers from?

 

From my huge collection of Jeep part numbers.

If you plan to do the carrier bearings...
I suggest you approach the axle rebuild as one should if they have no idea concerning the original shim pack thickneses.
In other words start out fresh with your setup by using the average thickness shim packs for each application.

I would not pull the differential case bearings right away.
You can use them in place and as-is for set-up fitment until you observe they need to be changed.

The very first thing you need to do is change the ring gear in case your doing that.
Next test the ring gear runout.
Measure the tooth runout (as opposed to back side of the gear face) must be less than .006".
Whenever changing ring gears the gear should be tested with bolts in 10 different possible positions on the differential case.
Check all 10 positions allows you to to achieve the minimum tooth face runout.

Next drive the new outer pinion cup # 02820 in place with zero shims.
then put .025" shim pack under the new # 31520 pinion cup and seat it.
Install a new # 31594 bearing under the pinion head.
Install pinion into its cups.
Add .065" preload shim pack onto the pinion shaft then install the # 02872 bearing.
Then the pinion yoke and old pinion nut.
Be sure to oil the pinion nut and threads and a few drops of oil on the new bearings.
No need for adding the outer pinion slinger just yet.
And no pinion seal until everything is perfectly set.

Tighten the pinion nut and if the pinion begins to bind then stop tightening.
Rotate pinion a few turns to fully seat bearings and cups.
Tighten pinion yoke to achieve a slight drag.
Add or subtract pinion preload shims as needed to obtain slight drag.
Or simply leave the pinion nut a little loose (for now) if not enough preload shims are present.

Time to approximate the pinion back lash.
I'll stop here for now.

You should be measuring all individual shims and also the entire shim pack used at each position.
You should be recording the numbers during all tolerance checks.

 

Thank you for all the info, it will help greatly on my rebuild.