I finally got around to taking things apart on my 97 TA and wanted to share
what I found so far and also ask a couple of questions. Once I had the
driveshaft out of the way a closer look showed that the leak was coming from
the splines on the yoke (area around the nut) and not the seal. The pinion nut
seemed to loosen fairly easily, probably not more than 40 ft-lbs torque to
move it. And the yoke came of fairly easily as well (just pulled by hand).

This rear end was assembled by a professional (I hope) about 10k miles ago
when I installed 3:73 gears. From the looks of it some type of clear RTV was
used for the yoke splines and nut, but a very limited amount. Although the
seal looks good I'll pull it and install a new one. From what I have read on
sealing the yoke, Permatex No. 2 is most recommended, and a liberal amount
on both the pinion and yoke splines.

Also for the record, the correct pinion seal PN is 26026792 (non-triple lip).

I marked the nut and yoke and will reinstall the nut with 1/16" (1.59 mm) turn
more per the factory service manual.

Questions:

- is it normal for the pinion nut to be installed with only 40 ft-lbs torque?
- is leaking through the yoke splines common? and if so why does the service
manual not mention sealant?
- is Permatex No. 2 the best way to seal the splines?

 

I'm in the process of installing 3.73s (replacing stock 3.42's). I pulled the yoke and it had silicone as well. I plan on using more on reinstallation, with a new seal, because there is fluid debris everywhere on the pumkin and surrounding parts.

 

I finished the seal replacement last night. The seal removal and installation
went very smoothly. I carefully cleaned the splines on the pinion and the yoke
and applied a liberal amount of Permatex No. 2 to both. I also applied several
drops of blue threadlocker on the nut threads and tightened the nut to the
original position plus 1/16" per the service manual.

It did not take much torque at all to reach the original nut position and the
additional 1/16", probably on the order of 15-20 ft lbs. Is this normal?

All that is left is to fill the pumpkin, drive, and hope the leak is fixed.

 

I brought this post back from the dead to say the leak is not fixed and in fact worse than ever. Since an in-car fix does not work I would like to know what you think the problem is? This was a supposedly professionaly installed R&P with all new parts which started leaking with less than 10k miles. I did an in-car pinon seal replacement, did it carefully, with a liberal amount of Permatex #2 on the splines.

Is the only option now to take the rear end out of the car and have it gone through?

 

Mine lasted 3k no leaks, then I put a S60 in. Having the rear out of the car is definatly easier to work on, but not neccessary.

 

I don't think I've ever seen one that did'nt leak.

 

I'm just going to pull the rear end out again and take it to a shop. If done correctly, the pinon seal should not leak at all.

On the bright side I did pass CA smog yesterday. So I'll have to look at the positives, plus the car is a great driver.

 

Just wondering if the problem was ever fixed? What did you end up doing to have it fixed?

I got the part from my dealer and had one of the local shops install it. However now its leaking way more then it use to.. I am talking about puddles in my driveway... The part number was... 26026792 Differential drive pinion gear seal (one piece pinion seal) non-triple lip. They did not even have the GM Rear Axle Pinion Seal Installer. They used some random pipe... Would this make a difference? I am pretty sure they did a bad job. Do you think I should take it to a speciality transmission place?

 

Hey numberformat,

I'm going to pull the rear end out of the car and take it to the local gear shop to fix it, hopefully for good. Mine only drips so the car is drivable but it's irritating.

 

pulling the rear axle out to service it is completely unecessary and a waste of time unless you dont want the ppl driving your car, but in all honesty, they need to drive it afterwards to assure correct assy. If you dont trust them with the car, I wouldnt trust them with the job. If you get it back and it aint right, you cant be too mad at them since they couldnt road test it. Ive never in my life heard of someone removing the rear axle and taking it to a shop to have it worked on, thats silly. Drive it over, and leave it.

 

I've sealed that pinion spline a couple ways. I've sealed it with blue locktite all over the splined part and the nut, and I've also done it with silicone under the washer and blue locktite on the nut. Both ways worked well and I didn't have any leaks but I prefer to just use blue locktite all over it because it makes less of a mess if you have to take it apart and redo it for another reason. That keeps it nice and tight and you need a puller to take it back off anyway. I've said it before that I believe a lot of the pinion leaks are through the splines and not the seal. That can happen up front, too, if there's a hole in the driveshaft yoke, but you don't notice it until you jack up the front of the car or put it on ramps for several hours.

 

I thought they were supposed to leak

 

The shop I trust does not work on cars, just rear ends. Plus I would like to know that everything is correct so they will be doing more than replacing the seal. While it's out I can clean it up nice (all that grime from the leak) paint it, clean the underside of the car, and be good as new when it's back in. After all, I'm about to hit 38,000 miles and I can't have it dirty on the bottom

 

How long did it take to replace the seal ? I'm not a mechanic like you guys so if somebody was cool enough to spell it out more than you already have i'd be in debt to you. I need to fix my leak and I'm nervous about doing it but at the same time it has to be done as the fluid gets low quick and the rear end howls.

I'd pay somebody but unfortunately the army doesn't pay a lot so I'm really hoping I can get it done myself. Thanks