JonRedcorn

So I've been replacing my inner axle shaft seals and axle u joints and noticed my pinion seems to be pretty darn sloppy. My front drive shaft also apparently needs replaced since it moves quite a bit at the slip joint or whatever that thing is called. The guy I bought it from did the drive shaft u joints, and they are all tight. It's just that middle joint that moves around. Anyways, I am wondering if it's possible the guy messed with the yoke bolt on the pinion and if tightening it up might work? If it doesn't I will take it to a shop and have them do the pinion bearings. The gears all seem to be fine and the carrier bearings all looked fine as well. No scoring or pitting at all. But the slop in that pinion is far from normal. The rear seal is also leaking. Would it be worth trying to tighten that yoke bolt up some? Or should I just take it in without the axles in and have them do the bearings.

The pinion moves side to side, up and down and in and out. It's pretty loose.... I can see two little marks on the pinion nut on the yoke where it looks like somebody took it off and did the mark it up thing, but considering the dana 30 has no crush washer I dunno why they would do that...

OldTires

This is tricky, mainly because we don't know what exactly was done with the pinion previously. The 30 uses preload shims to get the correct amount of preload on the pinion, so that when you tighten the pinion nut to spec (i think 150 ft lbs) there will be a certain amount of drag on the pinion when you turn it (this is with the carrier out of the differential. Some people who don't understand how the preload shim works take the easy way by putting the preload shims under the thick washer by the pinion nut. This is wrong and if you tighten the pinion nut to spec you will feel the pinion binding and being very difficult to turn.

If you have your differential open, you could take out the carrier, disconnect the yoke from the driveshaft, and turn the pinion by hand. See how loose it is. At this point you could also pull the yoke out, take out the pinion and inspect the bearings. Make sure to take careful note of how everything comes out, the order/position they are in. With the pinion out, now would be a good time to change the pinion seal. If all pinion parts look good, shims in the right position, then put it back in, get the yoke back on, and carefully start tightening the nut in increments to the spec torque. As you tighten the pinion nut, this will be your moment of truth to see if the preload shims are good/correct thickness. If you test the pinion by turning it by hand and it feels too tight and binding then the preload shim thickness is incorrect.

Needless to say, it's a lot of work and you will need some special tools to do it right. And if you need new pinion bearings, that's another level of work. It takes a lot of patience and time. Your Jeep will be off the road till you get it right.

Now if you feel like gambling, and want to try the quick and easy fix, you could just take off the pinion nut, carefully take off the pinion seal, install the new seal, and then tighten the pinion nut to spec. And hope everything is fine. But if it's not, then stuff will start breaking in the differential.

Good luck.

JonRedcorn

Pretty much what I figured. Think the best bet is just to take it to the shop without the axles in and have them fix the pinion. I rather spend 400 bucks now then 1500 later.

OldTires

The other option is to go looking for a new used Dana 30. Sometimes you can find them for cheap. Then you just swap out the whole front axle housing. It's a bit of work, but doable. The control arms bolts can be a PITA, but patience and effort can get it done. Of course you have to make sure the new used 30 is working right and doesn't have bearing issues.

I swapped out my Dana 30 because of rust issues and the new used had the preload shims in the wrong place. Someone had messed around with it and put it back together the wrong way. So I had to learn and redo the whole thing before putting it back in. Not fun, but cheaper than taking it to a shop to do it. It can get expensive.

JonRedcorn

The one good thing about this XJ is it has nearly zero rust on it. The few dana 30's I've found on facebook are all in worse condition than mine is. I'll call around tomorrow and see what kind of pricing I am looking at. I thought about dropping the axle out and just taking the whole axle to the shop. If I can get it done under 500 bucks or around there I am more than willing to pay that.

Jim Malcolm

Note,you have to have the outer axle shafts in; the nut holds the unit bearing together, it will come apart if you don't...

Replace the bearings bearings and run it... Tolerance on a quality bearing is on the order of 0.0001", much less than the wear on those gears and an order of magnitude lower than the nominal value and allowable range (0.008" backlash =/- 0.001" purely for example). If you decide to take it to a shop, spend the extra $200 and get new gears; penny wise, pound foolish otherwise. If you take it to a reputable shop, they're going to be honest with you: "Replace the bearings and run it or install new gears". Reinstalling used gears is bad-juju, which is basically what you're doing if you change any of the shims. Not saying that it wouldn't be a bad idea to measure backlash and check the pattern once back together just to make sure that you're gears are completely worn out; a magnetic base dial indicator can be found online for darn cheap.

JonRedcorn

Good catch I didn't even think of that... Also is it ok to install one set of gears? Or if I change the gearing up do I need to do both axles at the same time? I would assume the answer to that question is yes you need to do both sets. I'd very much like to have a locker installed as well. But again I don't know if it's worth it just yet. I'd like to put a LSD in it.

ijeeep

Different gear ratios front and rear is going to give you problems. You will have one end trying to go faster than the other, extra stress on the drive train parts and binding in the transfer case.

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JonRedcorn

Yeah that's what I figured, Thanks for the help.

JonRedcorn

Called three different shops around here and was quoted 1200 dollars at one and the other two never called back. Guess I am doing this myself.

97grand4.0

My rear pinion nut was loose 60.000 miles ago. Pinion howled over 30mph. So I tightened it up with a 1/2" drive craftsman ratchet. Gave it a couple knocks with a rubber mallet just to be sure. Only thing that happened since is it loosened up a couple more times. Each time I just tighten it again. I think a couple drops of red Locktite are called for on a rebuild, might help too. Not saying this is your issue, but it worked for me. With 215000 on it, yeah Id like it to be new but if a rebuild is not in the cards and you don't have all the right tools, it should get you by for the moment.
I wouldn't even consider letting a shop do it, unless you know for sure they know exactly what they are doing.

Dave51

Can you explain what you mean here? I can't envision why you need axles in and a nut on, and what falls apart if you don't have that. Thanks.

JonRedcorn

My carrier and pinion are both way too loose, somehow the gears still look fine and there was no metal in the diff. I tried tightening the yoke bolt down with like 4 feet of breaker bar and couldn't get it any tighter. I was quoted 450 to redo all the bearings in the diff, just gunna go to that shop. It's a bit further of a drive but everyone raves about how great it is and that price is right on the money cost wise.

OldTires

if they put the preload shims in the wrong place, it may be the reason why you can't tighten the pinion nut and take the slack out of the pinion. Like I said before, take off the yoke and slide out the pinion carefully, keeping all the parts in the position they are in - e.i. don't just let everything drop out. Once you have it out you can better inspect what the issue is. I big part of the job is taking everything apart, and you are mostly there already, so you may as well take out the pinion and see whats going on.

If I remember correctly, if you put too many preload shims (increase thickness), it will keep the nut and yoke from tightening enough to take out the slack. If so, this means you have the wrong amount of preload shims, which means will you have to find the right thickness of preload shims. Let's just hope they did not mess with the depth shims.

This thread helped me a ton:

CJ7 DANA 30 Full Rebuilt and Setup PART I - JeepForum.com

JonRedcorn

That's a great and detailed walkthrough. Thanks. Tomorrow I'll see if I can get the pinion nut off, I've ordered a spicer master rebuild kit, might use it myself or just take it to the shop. I am sure I could do this work, it's just, do I want to haha.