another diffy question

[ka50]

I have oil stains covered with dirt that is stuck to this oil all over the top of the differential and all the way up to the driveshaft... I mean it's like one huge stain. Where are the possible differential leaks are? What gasket is there that is between the differential and the u-joint?

How about axles?

[RallyRed 98]

pinion seal

[hockeyman]

Originally posted by ka50:
What gasket is there that is between the differential and the u-joint?
How about axles?

Pinion shaft is the thing thats leaking. It's right there between the diff and u-joint. They will always leak, it's the GM curse! I've already had mine replaced once for $300, and it was leaking a few weeks later. A few drops here-n-there every week are nothing to worry about. When you start getting a few puddles every night, then you may want to look into having the pinion seal replaced.
Axles could leak too, but it will be where the rear tires are. Not too common, and ALOT cheaper to fix than the pinion seal.

[ka50]

Any idea how hard it is to replace yourself? I don't feel like shelling out 300$ for a gasket replacement...

Does it have to be done from the inside of the differential or you can replace the gasket from the outside. Will it require disasembly of diferential? There's oil all over my differential cover and it's THICK cover. Also I get thumping noises coming from it when I shift gears... like it's about to fall apart or few bolts are loose...

[hockeyman]

The thumping may be your trans mount or bad u-joints. Check them first to see.
As for the pinion, yes, the gears must be ripped apart to access the seal. It's a PITA to fix, especially for the first-timer. If the leak is really bad, look into some shops and see what they charge. Or...ask around here. There may be someone local on this board that can do it for you.
Trust me though, once the seal is fixed, the leak will be back within time. GM curse...remember?

[ka50]

nah, thumping is almost defenetly from differential. When I was changing my brakes, I jacked the car up and listened to the noise.

But yeh, apparently it is pita to replace pinion gasket... you basically have to remove whole differential lol... I was thinking of swapping LSD while I'm at it... where can I buy one cheaply?

As for seal - I'll try to use some heavy duty sealmaker stuff.. maybe it will help.

[hockeyman]

You would probably save more money buying a whole rear setup. I bought my 3:23 posi disk rear from a local f-body junkyard for $150 complete. Darn thing is in excellent condition, but still has a minor drip from the pinion every once in awhile. Usually leaves a drop or two after a long trip (over 100 miles).
Once every 6 months or so I get under and check the fluid level. The rear has been installed since July of '02, and has not needed any fluid yet.