C5 Differential Leak
Thread Starter
Burning Brakes
Joined: Dec 2002
Posts: 1,157
Likes: 5
From: Eastern PA
C5 Differential Leak
Anyone have some insights? I am stumped as to a reason for my diff losing most of its fluid.
I recently had my local dealer check the differential fluid level as I was experiencing some noise from the rear end. They told me the fluid level was fine. There were no leaks before I dropped it off and no leaks upon picking it up.
After getting the car back, I immediately drove it about 3.5 hours to visit family. Other than a "nice" but tolerable whine coming from the rear end, nothing had changed from before I took it to the dealer. Upon parking at my destination, I discovered that fluid had come out of the left, lower side of the differential, coating my rear leaf spring. I put it up on some jack stands and saw fluid was also around the left axle area as it exited the differential and had splashed up onto the underside from having gotten onto the axle. The top, right and most of the bottom of the diff were dry and free of fluid. I did not see any cracks in the casing. Click on PICTURES HERE for photos.
I let the car sit for the weekend, putting some cardboard under the car to catch the drips from the rear end.
After the weekend, I drove it two hours to my chosen mechanic (a CF sponsor) who had installed the diff last year. Upon closer examination they told me that the casing did not appear to be cracked and that the left axle seal had apparently failed. They also told me that there was hardly any fluid in the differential and that they were at a loss to explain why most had leaked out, as the apparent failed seal should not have led to that massive amount of a loss. They suggested I check back with my dealer to confirm they did not add any fluid or that some idiot mechanic may have drained the diff and forgot to put fluid back in.
In a face to face with the svc dept this morning, the dealer rep swore on a stack of bibles that what he told me was true, that all the 'Vette tech did was as I requested--he checked the fluid level, which was o.k. No fluid was drained or added and there were no apparent leaks when I dropped it off or picked it up. All they noticed was the same whine that I did, but couldn't isolate it to the differential itself. Without any proof to the contrary, I have to believe what I was told.
Bottom line, my CF-sponsoring mechanic is tearing the diff apart as I type to see what kind of damage there might be...probably need to replace the entire assembly, casing and all. Ugh.
FYI, as implied, this differential does not have the stock internals (new 3.90s were reinstalled last year), but the stock casing was reused again. The case has 122K miles on it. The gear assy has 19K miles on it, which includes an 11K trip to and from Alaska last summer, two light track days (in the rain at Road America) and one hard afternoon at Summit Point - Jefferson Circuit. There has been no leak from the rear end in its entire history up until now.
So, anyone have any ideas on what might have led to, is the cause of, or what the actual problem might be? Again, both my mechanic and I are stumped as to what might have caused the diff to loose most of its fluid.
Insights, as always are much appreciated!
I recently had my local dealer check the differential fluid level as I was experiencing some noise from the rear end. They told me the fluid level was fine. There were no leaks before I dropped it off and no leaks upon picking it up.
After getting the car back, I immediately drove it about 3.5 hours to visit family. Other than a "nice" but tolerable whine coming from the rear end, nothing had changed from before I took it to the dealer. Upon parking at my destination, I discovered that fluid had come out of the left, lower side of the differential, coating my rear leaf spring. I put it up on some jack stands and saw fluid was also around the left axle area as it exited the differential and had splashed up onto the underside from having gotten onto the axle. The top, right and most of the bottom of the diff were dry and free of fluid. I did not see any cracks in the casing. Click on PICTURES HERE for photos.
I let the car sit for the weekend, putting some cardboard under the car to catch the drips from the rear end.
After the weekend, I drove it two hours to my chosen mechanic (a CF sponsor) who had installed the diff last year. Upon closer examination they told me that the casing did not appear to be cracked and that the left axle seal had apparently failed. They also told me that there was hardly any fluid in the differential and that they were at a loss to explain why most had leaked out, as the apparent failed seal should not have led to that massive amount of a loss. They suggested I check back with my dealer to confirm they did not add any fluid or that some idiot mechanic may have drained the diff and forgot to put fluid back in.
In a face to face with the svc dept this morning, the dealer rep swore on a stack of bibles that what he told me was true, that all the 'Vette tech did was as I requested--he checked the fluid level, which was o.k. No fluid was drained or added and there were no apparent leaks when I dropped it off or picked it up. All they noticed was the same whine that I did, but couldn't isolate it to the differential itself. Without any proof to the contrary, I have to believe what I was told.
Bottom line, my CF-sponsoring mechanic is tearing the diff apart as I type to see what kind of damage there might be...probably need to replace the entire assembly, casing and all. Ugh.
FYI, as implied, this differential does not have the stock internals (new 3.90s were reinstalled last year), but the stock casing was reused again. The case has 122K miles on it. The gear assy has 19K miles on it, which includes an 11K trip to and from Alaska last summer, two light track days (in the rain at Road America) and one hard afternoon at Summit Point - Jefferson Circuit. There has been no leak from the rear end in its entire history up until now.
So, anyone have any ideas on what might have led to, is the cause of, or what the actual problem might be? Again, both my mechanic and I are stumped as to what might have caused the diff to loose most of its fluid.
Insights, as always are much appreciated!
Last edited by kedvesh; Sep 14, 2010 at 02:25 PM.
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
You have the classic case of C5 leaky butt driver's side axle seal. It is not an "if" it will leak with C5s, it is a "when".
Thusly I promise you this...
is not true.
It may not have been leaking heavily, but I can guarantee you it was seeping somewhat. And while a catastropic failure of the seal like you describe is rare, it can and does happen. And that 3.5 hour drive very well may have been an unsuccessful stress test on an already compromised seal.
Thusly I promise you this...
It may not have been leaking heavily, but I can guarantee you it was seeping somewhat. And while a catastropic failure of the seal like you describe is rare, it can and does happen. And that 3.5 hour drive very well may have been an unsuccessful stress test on an already compromised seal.
Drifting
Joined: Apr 2007
Posts: 1,998
Likes: 33
From: somewhere in New Hampshire
Wow, I've never heard of anyone losing that much fluid but as mentioned I guess it could happen. My dealer replaced my seal for $400 which I thought was reasonable. Good luck, I hope your damage is minimal.
Thread Starter
Burning Brakes
Joined: Dec 2002
Posts: 1,157
Likes: 5
From: Eastern PA
Appreciate the intel, guys.
Found this thread via a search for "leaky butt" - http://forums.corvetteforum.com/c5-g...e-junkman.html.
However, based upon the catastrophic draining of most of the fluid--apparently while I was driving the car--I don't know what kind of damage there might be. Needed parts and required funds are yet TBD.
Found this thread via a search for "leaky butt" - http://forums.corvetteforum.com/c5-g...e-junkman.html.
However, based upon the catastrophic draining of most of the fluid--apparently while I was driving the car--I don't know what kind of damage there might be. Needed parts and required funds are yet TBD.
