Dana 30 inner axle seals, bearing wear, and carrier preload

On my 97 XJ, with the standard HP 30, I have had a problem with leaky inner axle seals and a wavy pattern on the ring gear side carrier baring (non ring gear side is not wavy). Both sides have some grooves in them in less than 5000 miles.

First time I did it, I went by the 97 Jeep FSM which called for .008" preload to be added after end play is accounted for. I measured .088" end-play and added .008" to get a total shim stack of .096". It was a replacement housing and I was told that inner axle seals were new, but the passenger side was installed crooked so I knocked it out and reinstalled.

When the passenger side started leaking I figured it was that crooked seal I re-installed, so I'll just change the seals with new ones. That's when I saw the wavy patter on the bearings. I replaced the seals and after playing around with setup bearings, etc. I ended up back at the original .096" shim stack. I put gear oil on the shafts and seal so they were definitely not dry when installed.

Then both sides started weeping gear oil after about 1200 miles.

This weekend I pulled it apart again, and found the same wavy pattern on the bearings. I replaced the seals with Spicers from the local Spicer dealer. I also re-did the shim stack after reading that Dana says .015" carrier preload not .008". I ended up at .012". I had been knocking in the carrier with a 2.5 lb dead blow, and needed a 4 lb dead blow to get it in with .012" (.100" total shim stack). At .102" I could not beat it in with the 4 lb dead blow.

I can understand that the wavy pattern could be from deflection of the housing/tubes under load. What I don't understand is why the Jeep FSM calls for .008" when Dana says .015". Measuring end-play at .088" and using .088" worth of shims, I could take the carrier in and out without any prying. At .090" I needed a small pry bar. So I think my starting point was accurate.

Any thoughts?

Without a spreader, I set open d30s so I just have to tap it in with light blows. Never hit the races, always the case. The outer races are kinda delicate, I have found through the years, and they warp easily. also, 55 ft lbs for the cap bolts.

Anything with a locker, or one that I want to set tighter like a WJ 30, a case spreader is definitely needed so the races don't distort on the way in.

Done either way, no failures that I know of, to date.

Other thoughts..

The seals leaking could be install error or a warped/bent tube or housing.

Making sure the axles themselves are not rough or pitted in the sealing area. That can destroy a seal quicker than you think. MAke sure the seal lips are lubed liberally before you put the carrier in.

Make sure the tubes are spotless so the axle doesn't carry dirt with it o the way in.

Thanks Don.

This time I shoved a old, clean tee-shirt from the center out on both sides and lubed both the shafts and seals with Vaseline. The passenger side axle shaft is a new Spicer, only has about 10,000-15,000 miles on it. I don't see any grooves. I've replaced pinion yokes when I thought it was appropriate. Always been hitting on the case center, never the bearing cups/races.

I ordered a spreader from Amazon but it came used, torn open manufacturer box and even the Amazon box so it's going back. I have a Miller on order now. If it leaks again, I'll use it, and if not, it will help out with future installs on the D44, etc.

To do it without a spreader, just put the carrier in the freezer for a few hours to shrink it and put your axle in a hot location like outside in the sun to expand the housing. And it will slid right in when you install it. Put a lot of gear oil everywhere because lots of condensation will form on the carrier. I've done this 5 times with great success.

I thought I was getting a bit of whine from the differential so I took it apart again. I found the backlash was .085-.009", not the .008" I measured when I first installed. I didn't think that small a difference would matter, but I took it apart anyway. I thought I would reshim and get it down to .007".

I was perplexed at the results:

original install was .008" with these shims, after 200 miles of driving:
.057 --- .043 .0085-.009

then tried:
.060 --- .040 .005 - .0055
.059 --- .041 .005 - .0055
.058 --- .042 .0055 - .006

If I kept going, I would have been back to .057 --- .043 which was the original install so I concluded something was wrong.

So I reduced the preload down to .008 and tried .054 and .042 with the bearings and was at .0055-.006 for a few spins of the carrier and then started reading .008 ??? With the same Koyo bearings in the past .054 and .042 would read .007-.008".

Each time to seat the carrier I was spinning the pinion back and forth, back and forth about 10 times.

As it was a holiday weekend and the better stores were closed, I got some National bearings and put them in. At .054 and .042 I was around .008. Not far from the .007-.008 I was getting with Koyo bearings when all this started. I switched to .056 and .040 and was at .0065-.007 and put it back together.

It seems that when you load the carrier bearings with too much preload moving shims does not work as expected, or the bearings get damaged.

With the .008 preload the carrier knocks in with 2-3 whacks of a 4 lb dead blow on the carrier. To remove it, I put a tee shirt over the ring gear and turned the pinion. It persuades it out without the need for pry bars.

And so far the new Spicer seals are not leaking! party1: