M6 Tranni and Diff overheat at high speed
Thread Starter
Instructor
Joined: Oct 2001
Posts: 144
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From: Montreal Quebec
M6 Tranni and Diff overheat at high speed
I've heard that at sustained highspeed, the M6 tranni and diff have a tendency to overheat. Has anyone experienced this and if so, what was the resolution?
Melting Slicks
Joined: Jul 2000
Posts: 2,483
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From: Wilmington DE
Re: M6 Tranni and Diff overheat at high speed (Straightpipes 1HD)
Welcome to the Forum Straightpipes 1HD. Unless you are racing your C5 you shouldn't have any problems with your Tranni and Diff getting hot. The Diff has synthetic lube in it from the factory and many of us have put synthitic Dexron ATF into our 6 Speeds.
I've run on the track for periods of an hour and have never had any problems with the Diff or the Tranni, and I'm sure that they were very hot. Normal street driving or drag racing should not get the oil hot enough to cause any problems. Best to you and you C5. Happpy Holidays :)
I've run on the track for periods of an hour and have never had any problems with the Diff or the Tranni, and I'm sure that they were very hot. Normal street driving or drag racing should not get the oil hot enough to cause any problems. Best to you and you C5. Happpy Holidays :)
Instructor
Joined: Feb 1999
Posts: 189
Likes: 2
Re: M6 Tranni and Diff overheat at high speed (Straightpipes 1HD)
Straightpipes 1HD
I agree with Jim 47, but will add a little about the exception of very high speeds for long periods. Having enjoyed 7 open road runs in Nevada, the last hit 182 mph (gps speed, 185 on the HUD), and averaged over 157 for over half an hour. Believe me when I tell you that the C5 desperately needs the diff and tranny coolers to do so. My previous two coupes, both lowered, were truly smokin' from the rear end about 20 minutes after the start, if I averaged over 145, which a C5 will do easily in 6th. To average much over that you'll need to stay in 5th exept for the down hill stretches or have a little tail wind so you can upshift to 6th and continue there. Not many folks have seen the shift light on the HUD in 5th I wager. Even Red Line in both didn't keep the diff from frothing oil out the vent on the runs where I stayed in 5th most of the way. No apparent damage was ever done, but it is an absolute mess to clean up and required changing fluids after the runs. I may run again some day but not at those higher speeds without coolers on both. Lowering is great for handling and lower drag, but also decreases the airflow across the the diff and tranny, making it harder to get rid of the heat. My Z06 I love for the improved handling, not the top end. Enjoy these holidays as if they were your last. Bless you all.
Booms
I agree with Jim 47, but will add a little about the exception of very high speeds for long periods. Having enjoyed 7 open road runs in Nevada, the last hit 182 mph (gps speed, 185 on the HUD), and averaged over 157 for over half an hour. Believe me when I tell you that the C5 desperately needs the diff and tranny coolers to do so. My previous two coupes, both lowered, were truly smokin' from the rear end about 20 minutes after the start, if I averaged over 145, which a C5 will do easily in 6th. To average much over that you'll need to stay in 5th exept for the down hill stretches or have a little tail wind so you can upshift to 6th and continue there. Not many folks have seen the shift light on the HUD in 5th I wager. Even Red Line in both didn't keep the diff from frothing oil out the vent on the runs where I stayed in 5th most of the way. No apparent damage was ever done, but it is an absolute mess to clean up and required changing fluids after the runs. I may run again some day but not at those higher speeds without coolers on both. Lowering is great for handling and lower drag, but also decreases the airflow across the the diff and tranny, making it harder to get rid of the heat. My Z06 I love for the improved handling, not the top end. Enjoy these holidays as if they were your last. Bless you all.
Booms
