Pinion seal replacement

[Zoro]

Noticed the rear axle pinion seal on my '84 is starting to leak. What's the torque spec for the nut and is there anything special to do while in there? Basically just remove the nut, yoke, seal and install is reverse of that, right?

[AMC of Houston]

Well, there is no actual foot-pound torque spec for that nut.  That's because its supposed to be torqued to compress a crush sleeve under the pinion bearing to a particular "drag" factor (measured in inch pounds) when spinning an unloaded differential.   IMHO, you'd be OK torquing it to 60 pounds or so, then check for any "up and down" play on the pinion.  If there's play, you may need to tighten it some more to get rid of the play (ie; to compress the crush sleeve some more).   

The manual actually says the torque spec to be "original rotating torque plus 5 inch pounds".   So to do it "right", you'd ned to take a rotating torque reading before disassembly.  Then tighten the nut to the new rotating torque spec.

Good luck with it.

[Zoro]

Explain the rotating torque reading? I think I understand but would like to be sure.

[eaglefreek]

You should really use a dial torque wrench to check for pinion preload. A beam one will work also, but a little more difficult to see exactly what it's pointing at when you're rotating it. Many get lucky when just using an impact wrench, but it's easy to overcrush the crush sleeve and throw everything out of whack and either ruin the gears or the pinion bearing. Here is a post from another site that shows the correct way to do it. http://www.jeepforum.com/forum/f12/dana-35-pinion-seal-replacement-question-722425/index2.html#post10170755. Here's the whole thread with some other ideas like using a paint mark and counting the number of threads to remove the nut. http://www.jeepforum.com/forum/f12/dana-35-pinion-seal-replacement-question-722425/index2.html#post10170755.

[MortenB]

I just replaced mine; used a torque wrench to take the nut off (noting the required torque), replaced the seal, tightened the nut to the same torque as it took to take it off. 

I think this will be ok.  Anyone have feedback on my method?

[eaglefreek]

I just replaced mine; used a torque wrench to take the nut off (noting the required torque), replaced the seal, tightened the nut to the same torque as it took to take it off. 

I think this will be ok.  Anyone have feedback on my method?

You might get lucky and be fine. One thing you have to consider is that there might be some rust or corrosion present when taking off the nut creating increased torque readings that won't be there when you reinstall the nut.

[BenM]

I've had luck with the paint mark method and checking with a digital torque wrench that it's in spec. It's better to under-tighten and check it than to over tighten and now need a new crush washer.

Also, check for a groove and if it exists make sure the new seal is at a slightly different depth.

[carnuck]

Mine was finger tight when I got it. I torqued to 80 foot lbs and rechecked a week later. That was 10 years ago on my MJ.

[Zoro]

Mine was finger tight when I got it.

Just went to take mine out and it was slightly more than finger tight. Checked the play on the yoke before I removed the nut and there was no front to rear play just the normal side to side gear play.