So there I was....with a gear oil stain on my driveway. After crawling under the the truck, I could see that it was the pinion seal that was leaking. Having never worked on a differential before, I was wary of fixing it myself. But having graduated from the YouTube Technical School of Fixin' Stuff, I embarked on a journey to shade tree mechanic the pinion seal.

The first part went fantastic. The pinion nut came off with exactly 17 turns, the flange came right off with a gear puller, and the old pinion seal came right out. It looked like they used RTV silicon at the factory rather than an o-ring. No wonder it leaked after 8 years.

So I got the new seal in and the flange on. Then I started on getting the nut back on. I immediately noticed that it engaged the bolt 180 degrees out from where it came off. No matter what I did, I could not get it to engage at the exact spot that it came off. Despite this, I went ahead and started counting turns. At 15 turns (2 shy), it hit a freaking wall. So I put a breaker bar on it and turned it about another 1/2 turn and it was getting difficult to turn even with a breaker bar. I disengaged the park brake and started turning the rear tires. I could hear a slight whine coming from the bearings. So I turned the nut another half turn and then turned the tires again. The whine was gone.

I was at 16 turns, 1 shy of what it took to get it off. I debated turning it further, I really wasn't sure if I could turn it any further. So I put it back together and drove it around the neighborhood. It drives like it always has. No rear-end noise.

Even though it seems to be fine, I am a bit of a perfectionist, so I got nervous about it. So today I took it to a shop for them to do the job right like I should have done the first time. They told me that they would check the torque on the pinion nut and check the pre-load on the bearings. If it all is correct, there is no reason to take it all apart and replace parts. After all, the good news is that I did fix the leak.

So my question is not whether I should insist on a new crush sleeve and pinion nut. I know the tech answer to that and should have done that to begin with. My question is: what happens if I don't and the bearings do not have enough pre-load on them?

 

Too little or too much and your going to go out and buy a new set.
On the nut it could stress crack and the whole thing come a part.

Sean

 

You're going to have to punt.

These are single thread, not double thread parts, nor are they self threading so there is no way that the nut would start anywhere but at zero degrees from where it disengaged the pinion threads. You lost count (it happens) and your not at the right torque. The backyard, YouTube methodology can work in many cases, but not this time.

If the axle was supposed to have an O-Ring, in production there is no way that they would have substituted RTV. I would be looking to a situation after it came off the railway car if it varied from design intent.

 

My guess is that sometime between the build date of Jan 2005 and now, they changed the design of the pinion seal to add an o-ring. The old one does not have one, nor does it look like it ever did.

Thanks for the responses guys. I hope to hear back from the shop today about what they found. I think I'm just going to ask them to go ahead and replace the pinion nut and the crush sleeve.

 

I had a pinion seal leak and was getting ready to change the seal. It was slinging oil up on the body but no drip puddle when still. The cause of my leak was the diff vent hose end was clogged up. Where the hose attached to the diff was wet with oil. So I put a T fitting back in the open end of the vent hose and check it every oil change to be sure it is open. Never had another leak problem.

 

That was my hope, but I checked the vent and all was well.

I did get my truck back from the shop today and they said the pre-load on the bearing was "a little off", but the measured it and put it where it needs to be.

Now I have an opportunity to go open it up with the new Atlas 40 tune on it as well as the new Bilstein 5100's I put on it a few days ago.