Dean Gladney

8Vette7:

You were spot on with the left half seal, I had that issue at 30K on my 03 Coupe. Had it fixed, and the tech also replaced diff oil with the new recommended fluid. Now I have some clear oil leaking down onto the center of the rear cross member. Got it up on jackstands and did some cursory inspection, gonna get in there with my inspection camera today. You mentioned a vent in the diff. I'm wondering if that could be the source. Where is that located? Thanks in advance. Dean

Black 03 Z06

One other thing to check. When GM replaced the driver side seal on my 03 the mechanic apparently reused the crush washers for both drain plugs. It started to leak again and I was about to take back to GM (on my dime) to get it fixed again. On the off chance I had lost too much fluid to drive it a long distance I pulled the top plug to to up the diff. Found the washer bent into a perfect heart shape and when the diff got hot it leaked oil past the washer.

Cheap SOB's cost me concern and a messy job. The washers are expensive by the way and appear to be a one use only item. If the diff has been emptied before check at least the top fill plug. Maybe save you some time and money.

GCG

It is on top by the driver's side (the round and shiny little cap).

norcalace

Why are you blaming GM for a rubber seal that has sat idle for most of the last 12 years? Let me guess...you know absolutely nothing about automobiles? Did I get it right?

Sox-Fan

And you replied to a post from august 2014. I'm sure he's done thanking GM by now.

norcalace

Damn, I hate it when that happens. Glad I didn't PM him.

Sox-Fan

Lol!

zachaeous

When I purchased my 2001 I had a small drip of oil from the drivers side half shaft seal. I found the post on here about the differential vent and low and behold it was stuck. After replacing it and a little driving no more drips. Good luck with your repair.

Part number 19132947 vent was around $25.00.

Dean Gladney

Black 03 Z06:

Thanks for your reply, I'll pull the fill plug and see what that looks like, also if it's overfilled, I understand that if you're level, any overfill will spill out. I'll leave the drain plug alone for now, since pulling that will mean a full drain/fill. If the fill washer looks OK and the leak continues, back to the folks that did the left half shaft!

ROJ#79

My '99 was leaking about 10 years ago and I was told to change the rear end oil and install RED LINE Gear Oil and it never has leaked since.
I know it's hard to believe but it worked for me.

Black 03 Z06

Dean best of luck finding the problem. I would never have believed the washer issue if I had not done the inspection myself. Just make sure if you are under the car you have it well supported, work safely it is in a bit of an awkward spot. I used a marine lower unit fill pump to fill mine (what ever you do don't drop the tube in inside the housing). Just another hint, sit the oil container itself in bowl of hot water to make it flow easier out of the bottle. It is thick stuff. I used Mobil One diff fluid with the LS additive already in the mix.

Good luck.