ZR WON

Hello all:

I drove my 16Kmile '01 Z06 about 300 miles this weekend(and it was *hot*, 95+ degrees 110 heat index). Upon arriving at my destination, I found a bunch of oil specs(gear oil, not trans oil, not engine oil, differential fluid, it has a very specific odor) on the rear fascia. I looked under the car at the rear end and didn't see anything at the time. I cleaned the car and in driving around town, noticed no new specs on the rear.

Upon arriving back home, the fascia was again covered with oil specs. I backed the car up on ramps and had a closer look. It seems that it's coming from the drivers side halfshaft area, closest to the differential(vs. closest to the wheel). It had leaked enough that it had streamed back on the exhaust pipe(before it goes into the muffler) and fiberglass that goes b/w the exhaust pipes and started dripping on the floor(although it has not leaked anymore since I cleaned the area up). Interestingly enough it was not flung everywhere like one might think if it was leaking around where the halfshaft was spinning. It was more like it was dripping out and the wind from traveling highway speeds was blowing it back.

I know from researching on the Forum that there are two possible scenarios: 1) It is the differential side cover o-ring and left axle shaft seal, or 2) The diff was overfilled and coming out the vent at the top of the differential.

Question: If it was the differential o-ring/seal wouldn't the fluid be strewn all around the shaft(from spinning) and surrounding area or would it just leak out and be blown towards the rear of the car like I explained.

Or would this scenario more than likely be the vent seeping? I felt around the vent area and it didn't seem wet at all, it was mostly around the drivers side halfshaft/differential area. Any and all help is appreciated, the car has an extended warranty but I'd like an idea of the probably cause before bringing it to the dealer(for obvious reasons). Thanks in Advance

Brian A.
90 ZR-1
12.09@118
01 Z06

ZR WON

Anyone???

Johnny_B_Good

It looks like I have a leaking rear too. It’s on the driver’s side of an ‘01 A4 coupe. It too seems that it's coming from the driver’s side half shaft area, closest to the differential. This morning, I noticed a spot on the garage floor. Can someone tell me what I should expect to pay to get this repaired? Thanks in advance!

Leo the Lion

Welcome to the club! Very common with C5's as you know. Mine was the diff cover leaking. Fluid drips from the bottom of the cover and covers the botton of the suspension cradle and then air flowing under that car will carry it to the back fascia. All you can do is get it fixed and hope it seals up. In my case it took two tries to stop the leak. I had it taken care of under warranty both times so don't know how much it would cost. My car was in the dealership for two days the last time they replaced the seal.
Good luck

Jim2003

Today I took my 2003 MN6 in for the 4th time. Same sequence. Leak on the left side, drivers side. Mine happens at highway spped much more than around town. I am believing that it is related to the airation of the oil as the gears spin at higway speedsl. In town you stop at lights, you slow down around turns, you slow for traffic, etc. but on the highway the gears are always spinning. I will know somethings by Tues or Wed of this week, when I get it back. 21K on it is all, so still under warrenty.

ZR WON

Hello all!

Thanks for the responses. I have read on several other threads on this topic that many(too many) persons have had this done time and time again.. One particular thread mentioned that there is an updated fix(different o-ring and gasket) that will fix the problem properly with no reoccurance. Does anyone have the TSB with the *correct* fix; I don't want to be doing this again in 6 months... Thanks in advance

Jim2003... You are in Louisville, I'm just n. of you in New Albany. Who do you take it to? I hear Bachman is the 'Corvette dealer' in Louisville but I wasn't real impressed with them when i chatted with them. Bob Hook on the other hand was very nice and offered to assist in any way they could.


Brian A.
90 ZR-1
12.09@118
01 Z06

JEEP/C5

I just repaired my 01 A4 with the same exact problem ZR one described. Mine was the Left side axle seal (where the axle shaft comes out of the aluminum cover). I decided to do it myself (I could not give my baby to some stranger for 2 days). I have a fairly complete set of hand tools and air tools, GM owner’s manual and knowlege of CV joint repairs. Per the dealers advice I replaced the side cover o-ring as well. Looking back at the project - since it was obvious it was the axle seal only - I could have saved 2 hours by just replacing the seal only while still installed on the rear end. The seal is an updated version from my 01 (looked a little different when I compared them side by side too). If you just replace the seal only expect 3 hours, 4 with setup and clean up. If you do the cover o-ring too - 5 to 6 hours - I took me extra time and check every thing twice and cleaned up 99% of the mess it made under the car (dealer will not do this). Worked out fine and no leaks after a week and 100 miles! E-mail me if you decide if you want to do it your self and I will answer any question. The deal showed aprox 2 hrs labor @ $65 per hour and the seal cost $17.32, o-ring $20.66, 4oz limited slip lube - $7.65, 2 quart syt. 75w-90w gear lube, $9.99 (auto zone, dealer lube 19.99 each) Hope this helps.

Jim2003

ZRWON, I have used Bob Hook Chev every since 1997 when I bought my 97 Z-28 from them. My Vette was ordered from them and only goes to them. Bachman Chev has a quote big reputation, but does not follow through. Read my post about my neighbors Z06 and the hole they poked in his floor pan. E-mail me at jvnelson68@aol.com We can talk and I'll tell you my service write man who is the best.