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D30/D35 pinion seal replacement

8K views 19 replies 12 participants last post by  barty 
#1 ·
The seal is leaking on both my diffs, where the driveshaft goes into the diff. The pinion seal I assume..

I did a little reading on replacing these and there is info about needing an inch pound torque wrench, and pre-loading the bearings to 300+ ft lbs..

Is this something I need, or can I replace these seals on my own? I can buy new seals from napa for about $20 each, so if I can do it myself I'd like to avoid taking it in. I don't have a torque wrench that goes over 100 ft lbs, and I don't have a press for the bearings.. am I **** out of luck?

I can likely borrow a large torque wrench (up to 700 ft lbs) if needed from work, and I have a press at work if needed.. but I'd prefer to do it in the garage.
 
#2 ·
I did mine on my own. I used an impact to get the nuts off to remove the yoke. I used a breaker bar with a pipe to put them back on. It has been over a month have done wheeling and lots of driving and have had no problems. I did not do anything with my bearings though.
 
#3 ·
The "correct" way to do it is to replace the bearings and crush ring and install a new pinion nut torqued to the factory specifications and all that other stuff that no one ever does.

The way everyone does it is to take the thing apart, throw a new seal in there and tighten it up to around 190 ft/lbs. To get my pinion nut off, I ended up sticking a jack under a 1.5" bar to break it loose. You'll be fine.

Might not be a bad idea to invest in a decent torque wrench, though.
 
#4 ·
You set the preload with an INCH LB torque wrench, not 300 ft lbs!
There's a crush sleeve in both those diffs and you are supposed to measure the preload before you pull the pinion nut then when you reassemble you set the preload to the same + 5 inch lbs.
Better do some more reading on this. If you overcrush that sleeve your diff won't be working right very long.
Jim
 
#5 ·
Hey it's not my words, it's others. Looking at different write-ups online they state the pinion nut should be put on anywhere from 150ft lbs to 300 ft lbs.. seems the most common used for a d30 as an example is about 160ft lbs-220ft lbs.

"and the Dana handbook calls for 200-220ft lb."

Anyway, I did see someone saying that if you mark where the pinion nut was before, and replace it to the same spot + 1/16th of a turn it should be very close.

Anyone ever tried this?
 
#7 ·
I'm using this write-up to do my D30 pinion seal in the next day or so.

http://www.jeepingsingles.net/tech/pinionseal.asp

Written by a buddy of mine and it seems very straight forward..

Except the torque upon re-installing the nut, that I do not know..
 
#8 ·
I see a expensive garage visit in your future.....DO NOT follow that write up,look in the forums for the proper info.
The info in that link you posted is so GENERAL its just enough info to get you in so deep you'll have such a mess you won't know what to do.
 
#12 ·
Once the crush collar is installed it is IMPOSSIBLE to use it again....forget about it.THERE IS NO TORQUE SPEC FOR REUSING THE CRUSH COLLAR!Because its useless once its been crushed.The proper method is to mark the nut and retighten 1/16 inch past the mark.ANY OTHER method is useless IMO.I've done 100's of rears that others have "replaced the pinion seals"trust me on this.
 
#14 ·
If the 'Do it Right' crowd says you have to go by the book which means a new crush sleeve which means the pinion gear has to be pulled, then count me out of that crowd. I doubt many would claim Tom Wood's advice is anything but unimpeachable and that's what I go by when replacing a seal or yoke.
 
#18 ·
Mark the nut and outside with something (a small tap with a punch will do), and count the turns to remove it.

When you put it all back on, line up the punch marks, and give it a 16th of a turn more.
 
#16 ·
Jerrys method is good because you confirm the nut is plenty tight without OVER TIGHTENING.But i would still mark it 1st to be sure its past the mark when you are finnished AND NOT TOO FAR PAST IT that its too tight.I think this clears the nut tightening mystery up.

Using Jerrys method you would start to get torque readings in the 100-150 range then check the mark.Continue until its 1/16 inch past and the TQ wrench confirms you are good and tight.This methjod is probably the safest IMO unless you are a pro and know what to feel for.

I have to warn you i have seen many rears that the bearing preload was tight and torque reading on the nut was low.......very low like 30 ft lbs....thats why its important to mark that nut.


pssst ...i'mma pro...LOL
 
#19 · (Edited)
just did mine using the "mark the nut and count threads method" then set torque wrench to 160 and tightened.

nut ended up approx 1/8 of a turn past where it was originally.

i would like to add that i still have the bar code sticker on my diff which i though was pretty cool for a 10 year old jeep, i'll post a pic

 
#20 ·
That method is completely passable if you're just replacing the pinion seal. To check the bearing pre-load, you're going to have to remove the axles and carrier, since you're just trying to measure the amount of force required to rotate the pinion gear with a load on the bearings. That's probably more work than what most people are bargaining for just to replace a seal.
 
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