Hey guys - 88 GTA 140K on it. I haven't driven the car much over the summer, but did get out on a few rides during the Fall. Runs like a champ with no problems whatsoever. Last time I took it out was 4 days ago. There was nothing on the garage floor.

Today however, I pulled the car out and went back into the garage to notice a pretty significant pool of gear oil on the floor. I immediately went underneath the car to see if I could find the source of the rear end leak. And nothing readily obvious was showing up.

The rear diff cover is perfect. Not one drop of oil coming from it. The area where the uJoint meets the rear diff has had some thick gunk on it for quite a while. Nothing major, but definitely visible. Yet I never saw a drop of oil on the floor until today. And the pool was big enough to warrant some concern.

I have a feeling it's the pinion seal. But why don't I see any visible drops of gear oil coming from it? If all that fluid came out, I would imagine I'd see some type of drip residue leftover.

What do you guys think? Any advice? (obviously I know not to drive it; but anything else would be extremely helpful)

 

I would clean the gunk off and top the gear oil off to see how much leaked and to see if it continues to leak, i'd also check the brake fluid, the rear brake lines run close to there

 

That comes across as an oxymoron. You know; "jumbo shrimp", "civl war", military intelligence", "feminine logic", "masculine sensitivity", etc.

Seriously, a pool of fluid underneath a part that contains that fluid, is pretty damn strongly visible leakage. It's pretty much a given that the part in question has a leak. Rather than "no visible leak", the operative concept should be, "haven't seen where it leaks, help me find it".

First and best way is, look at the pool of fluid, then look straight up. Not brain surgery really. You'll see a drip or something that will lead you toward the source.

Most likely, it's coming either from the gasket or from the pinion seal. (assuming it's under the center of the rear... is that where it is?) If it's under a shock, it's that shock. It might be from something to do with the brakes as well. And so forth.

Once you narrow down the region it's coming from (left, right, center, toward the front, toward the rear, etc.) take it to the quarter car wash, along with your floor jack and stands and acoupla cans of engine degreaser; put it up in the air where you can slither under it and get real personal with it; spray everything (that's EVERYTHING, with a capital "V") around the suspect area with degreaser; let it soak for 10 minutes or so; spray it again; let it soak another 10 minutes; then blast the hell out of it all with the Soap function. Repeat as necessary until sterile. Works better when everything is good and warm, like after a 20-mile drive on the freeway. Then take it back home and drive it up on your Rhino Ramps and crawl up under it and inspect thoroughly. Shouldn't be hard to spot.

 

Also make sure the vent for the rear end isn't clogged. If it is it will blow out the seals. Had it happen on my daily...

 

Yes take a good look at the pinion seal.

 

Make sure the plug has Teflon tape on the threads to seal it up.

 

Thanks guys. I am confident it is gear oil. The smell alone is the dead giveaway. The car has sat parked for days and not one drip. I will be pulling it out this afternoon to see if shifting/moving forward will cause any new leaks. The fill plug is one of those snap in ones. It doesn't have threads on it so I can't Teflon tape it.