Leaking rear end 95 Tahoe

[a4gb1]

I have a 95 Tahoe that just started to leak a small amount (.50 cent piece) puddle of rear end fluid when I park. The location of the fluid is directly below the differential. I checked fluid, added and still leaks. Any idea's on what to check for?

[95tahoe4x4]

Where is it "wet"? directly on the bottom? If so, good news, remove the bolts, pop the cover, careful it will be messy, and drain it all out. When it is drained, clean the old gasket off, put a new one on (I have never used a gasket, black silicon works fine - and it has never leaked), but some people will say you have to have the gasket, either way use black silicon. With the cover off, inspect the gears, check for bearing wear, etc. Place the cover on, bolt it up, and fill it up. When taking the cover off, use a rubber mallet, do not use a screwdriver to pry it off, you could bend it. A couple of good smacks should get the cover to pop off.

Kt

[GMMerlin]

I would disagree about the silicone sealer..I would recommend using a gasket..alot less chance of leaks.

Look at the differential and see where it looks wet..there are only a couple places fluid can leak from..cover gasket, pinion seal, fill plug, where the tubes are pressed into the housing and at the axle seals.
Depending on where the leak is will make a difference on how easy the job is.

[a4gb1]

No I don't think it is exactly at the differential. The fluid seems to take the path to the middle of the rear end being it's lowest point of the car to the ground. I think the leak is happening where the universal joint joins the rear end (not exactly sure what that would be called). I wish I had some kind of diagram that would show the drive train of the Tahoe.

[a4gb1]

What exactly is the pinion seal? I don't believe it to be the cover gasket and around the fill plug everything appears to be dry. To me it looks like it actually is traveling from the U-Joint area down to the rear end cover, collecting, then dripping off dead center under the rear. Does this make sense?

[GMMerlin]

Yup..sounds like the pinion seal is leaking

[95tahoe4x4]

PINION SEAL! Oh well, from the sounds of it you should take it to a repair shop. This is not something that should be attempted by the mechanically challenged. If you have a good air gun and the time get a $5 pinion seal and do it yourself, I would pull the rear cover just for inspection sake. Gm merlin: disagree as we will on the silicon, what ever works, I will admit the gasket is easier to get off.

Kt

[GMMerlin]

Originally Posted by 95tahoe4x4

Gm merlin: disagree as we will on the silicon, what ever works, I will admit the gasket is easier to get off.

Kt

I guess with your years of experiance in the automotive field far outwieghts mine.
Now tell me why GM got away from using silicone sealers on differentials and went back to a gasket?

[95tahoe4x4]

Easy there big guy, no where did I ever state that my years of automotive experience out number yours. Nor did I ever claim to know it all about when GM made such a switch. Your vast mechanical experience is a huge benefit to this board. Many people look directly to you for answers, and you do help them. I can speak for many who post here that your knowledge is an asset that many seek.

For me, by my experiences, in my own rigs, using silicon has worked just as well as using a gasket. I see it used in the shop many times for diff covers and in the 6 years I have been there I have yet to see one return for a leak. I do believe I stated that people will disagree with this, but hey: to each his own.

People post here to get opinions/tips on how to fix things, I, like you have a right to toss out my 2 cents. If you disagree with the opinion/tip then simply state it, (as you did in your first post) but to call someone out to the mat over such a trivial issue seems, well a little childish. If I have in some way bruised your ego on this, well, tough.

Kt

[GMMerlin]

Originally Posted by a4gb1

What exactly is the pinion seal? I don't believe it to be the cover gasket and around the fill plug everything appears to be dry. To me it looks like it actually is traveling from the U-Joint area down to the rear end cover, collecting, then dripping off dead center under the rear. Does this make sense?

Pinion seal is behind the flange where the driveshaft connects to the differential.
Although the job isn't to bad, I would highly recommend that you find a tech who can handle the job..this is not a job for someone that doesn't know exactly what to do.
The flange is torqued to preload the bearings that support the pinion. There is a rotating torque spec that must be maintained otherwise you could put too much preload on the bearings and cause a failure.
This is a common (and costly) mistake made on this type of repair.