Rear end leak
Thread Starter
Intermediate
Joined: Mar 2008
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Rear end leak
I'm looking at a 01 Z06 but it has a leak on the rearend somewhere. I'm a little scared I'm getting a project I dont want. Does anyone know anything about this?
Last edited by RRR Racing; Mar 18, 2008 at 03:41 PM.
Safety Car
Joined: Jun 2005
Posts: 3,561
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From: Clark NJ
St. Jude Donor '05 thru '26
This was taken from the C5 General sticky. Mine was leaking on the drivers side. I had mine fixed by a reliable Vette shop here in NJ.
"Leaky butt
The differential can leak from the side covers. The problem has to do with the design. The lip on the casing is not wide enough to create a proper seal with the cover. Resealing the covers can be successful, but many dealers do not use the correct sealant."
"Leaky butt
The differential can leak from the side covers. The problem has to do with the design. The lip on the casing is not wide enough to create a proper seal with the cover. Resealing the covers can be successful, but many dealers do not use the correct sealant."
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
I would say move on. I passed on plenty of leaky C5's until I found mine. They are out there.....keep looking.
Drifting
Joined: Apr 2000
Posts: 1,390
Likes: 35
From: INDIANA
My '01 came a good bit overfilled from the factory, making it look like it had a leak. Fresh lube, at the proper level, no more problem. It could be that if someone has changed the lube and overdid it.
Le Mans Master
Joined: Nov 2004
Posts: 7,050
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From: Canadian Rockies
My C5 has a "leaky butt" as well but I believe it's coming from the output shaft - the most common type of rear end leak on the C5's. The dealer quoted $300 but I'll probably do it myself thanks to some instructions from Cajundude :
http://www.cajundude.com/outputshaftseal.htm
http://www.cajundude.com/outputshaftseal.htm
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
If the rest of the car is really good, you can use it as a bargaining chip. If the rest of the car is telling you there was some abuse, then move on. Unfortunately, many cars (even those that were babied) had this problem and it is pretty common. A friend was looking at a car a couple of years ago and the car was perfect and had been absolutely babied. He asked me to look it over for him, with the owner standing there who was very proud of this car. First thing I did was crawl under and sure enough, there was the leak and the owner wasn't even aware of it. He was very **** (like myself) and had the car repaired a couple of days later.
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Thread Starter
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Joined: Mar 2008
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Thank's for the input. Its a Torch Red 01 with 42k and it has a few mods. Pretty clean car with ccw wheels and the tires are in real good shape. A 60 year old gentleman owns it. I'm not sure how much abuse it has seen but I can get it for 25k.
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
Still much to consider here. Get the car checked out. Check the DTC for codes. Inspect the battery area for prior leakage. Does the owner still have the original wheels and parts removed for mods? Have the vin run for service history.
Thread Starter
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I took this car to the Pontiac dealership where I have a buddy that works there. The rearend is leaking between the transmission and the diff. Looks like someone at sometime put some rtv in the seam to try and slow down the leak. The owner is not willing to lower the purchase price to fix the rearend. What kind of a job is this? Anybody?
Le Mans Master
Joined: Dec 2001
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From: Winchester TN
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St. Jude Donor '03-'04-'05-'06-'07-'11
I took this car to the Pontiac dealership where I have a buddy that works there. The rearend is leaking between the transmission and the diff. Looks like someone at sometime put some rtv in the seam to try and slow down the leak. The owner is not willing to lower the purchase price to fix the rearend. What kind of a job is this? Anybody?
Hi RRR -
You have to remove the diff of course - that means lowering the suspension cradle.
If you read cajundude's seal write-up, you essentially do that same disassembly process on both sides, and then detach the brake lines and electric harness from the cradle, remove the two 13mm bolts that hold the differential to the cradle, and then you are 4 21mm nuts away from the cradle lowering down and away from the car - shocks, rotors, halfshafts and all.
Sounds like a ton of work - in reality it is easy and takes a couple of hours if you go slow and take your time.
The diff is bolted to the trans with several 13mm bolts.
Then you will be at the source of the leak - the trans output shaft inserts into the diff , and there is an open "window" on the front side of the diff.
On the diff swap I did a couple of weeks ago, we used silicone sealant around the mating surfaces on re-assembly.
This job is not a big deal, and still not something that I would queer the deal over if I really liked the car.
best regards-
mqqn
Tech Contributor
Joined: Jan 2007
Posts: 19,398
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From: Dyer, IN
I took this car to the Pontiac dealership where I have a buddy that works there. The rearend is leaking between the transmission and the diff. Looks like someone at sometime put some rtv in the seam to try and slow down the leak. The owner is not willing to lower the purchase price to fix the rearend. What kind of a job is this? Anybody?
1) He was too lazy to get it fixed, and tried to seal it up.
2) He was trying to mask the problem, and unload the car
3) The rear end has been removed at one time, and someone rtv'd the surface (which it's not suppose to be).
Based on the way it sounds like your leaning, I'm sure this caution falls on deaf ears blinded by the prospects of buying your first C5. Just remember, there are plenty more out there in better shape for the same money, and have been well maintained. You just have to be patient.
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Thank's for the information. His take on it was he will just keep putting grease in it and drive it. The car at one time had a super charger on it so that kind of worrys me. Both the transmission and diff poured fluid out when we took the fill plugs out. The fluid in the trans was dirty and had a little metallic color to it (slightly gray). It also had a lean left and right bank code. My buddy thought it might be a intake gasket.
Banned Scam/Spammer
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From: Simi Valley CA
The 01 Z had ring problems anyway. If it were blown to boot, I think I'd stay clear. Too many other ones out there. If you can find a > 02 you'd be better off. Read up, there were several changes that added a few more ponies to play with.
Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
Thank's for the information. His take on it was he will just keep putting grease in it and drive it. The car at one time had a super charger on it so that kind of worrys me. Both the transmission and diff poured fluid out when we took the fill plugs out. The fluid in the trans was dirty and had a little metallic color to it (slightly gray). It also had a lean left and right bank code. My buddy thought it might be a intake gasket.
Team Owner
Joined: May 2005
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From: Flagstaff Az.
Also a grey color in the fluid indicates metal and that can not be good news. I would move on. 
Le Mans Master
Joined: Dec 2001
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From: Winchester TN
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St. Jude Donor '03-'04-'05-'06-'07-'11
RRR -
I am not sure you are getting clear info here.....
First - the seal between the diff and the trans on a C5 corvette with a manual trans does not have o rings - and it does use sealant.
Here is a picture of that area from another site -
You can see that there is a large hole that I described above - if you do not seal the mating surface there will be a nice leak there.
A4's use a "seal plate" and do not require the sealant.
So - yea, if the diff is cracked or broken, you might be looking for a diff - which by the way can be found for $600-$700 for a nice used one.
Also - speaking to the 01 oil use issue - that is totally overblown and very few cars actually had the problem to the extent that GM replaced the rings etc -- some DID, but very few had a problem - and many that did have the problem were fixed by GM.
The trans fluid will get discolored by the carbon synchro's in the later tremec transmissions - not necessarily a sign of a worn out trans.
When I changed mine out for the first time after 36k miles it looked black and cruddy. My trans works fine still after many trips down the drag strip and 54k+ miles.
best regards-
mqqn
I am not sure you are getting clear info here.....
First - the seal between the diff and the trans on a C5 corvette with a manual trans does not have o rings - and it does use sealant.
Here is a picture of that area from another site -
You can see that there is a large hole that I described above - if you do not seal the mating surface there will be a nice leak there.
A4's use a "seal plate" and do not require the sealant.
So - yea, if the diff is cracked or broken, you might be looking for a diff - which by the way can be found for $600-$700 for a nice used one.
Also - speaking to the 01 oil use issue - that is totally overblown and very few cars actually had the problem to the extent that GM replaced the rings etc -- some DID, but very few had a problem - and many that did have the problem were fixed by GM.
The trans fluid will get discolored by the carbon synchro's in the later tremec transmissions - not necessarily a sign of a worn out trans.
When I changed mine out for the first time after 36k miles it looked black and cruddy. My trans works fine still after many trips down the drag strip and 54k+ miles.
best regards-
mqqn