KRPTONT

Well true to the rumors I was at a track event Friday-Sunday. Friday was play day at Hallett, went out for the first round maybe 20 minutes car performed awesome. Went back out hour later and was into the 3 lap and the DIY started dinging ideal speed transmission temp high. So I idled off an the temp was like 300*. Wow! Talked to several race friends and called 4 dealerships. All say the same thing. Known problem but nobody knows what to do. Saturday and Sunday events were just 2 laps at a time. The temp was fine highest was maybe 190* so yesterday I spent the day at my dealership contemplated changing tranny fluid but the dealership and I decided not to. Did change the rear axle fluid because the owners manual says to after the first track and I read LATE that I needed 15/50 oil. I will put that in on Friday. Well my questions to all with the A8 anybody else have this happen, what did you do about it. I only do like 3-4 high speed events a year but several auto crosses. I do not want to do anything to void my warranty either. Any suggestions would be great. Thanks in advance.

eboggs_jkvl

Only recommendation by GM was to order the M7. The A8 overheats.

Not sure if they fixed it even on the Z06. I read the A8 overheats on that too.

Elmer

Magister Ludi

Several threads on this. Most effective fix thus far seems to be wrapping the exhaust pipes near the tranny.

clegg

This and a member installed a Dewitts Radiator.

eboggs_jkvl

Is the engine overheating too? I thought it was just the tranny.


Elmer

5thGear

Just to confirm, you do have a Z51, right? Did you shift in manual? did you shift at redline? what was the ambient temp at the track.

I was at the track two weeks ago in 90F weather in my 2015 Z51 A8. Transmission was getting up to 260F at the end of the 20 min session but that's it. I do have Borla xpipe and I did wrap the exhaust by the transmission.

5thGear

Z06 A8 transmission doesn't over heat since it does have a larger transmission cooler as well as a secondary cooler that the Z51 doesn't have. The problem with the Z06 is the engine overheat.

Greg00Coupe

And did not Tadge say you know if you want to track the car and avoid overheating..........steer clear of the auto?

eboggs_jkvl

I thought I read that there also...

5thGear

GM keeps on saying that the A8 shifts faster than the Porsche PDK. So this means its a faster car than manual. Would I want the faster car to go to Starbucks? Absolutely not. I would want to drive it on a racetrack. Porsche even dropped the manual from their performance cars lineup. Tadge needs get his engineers to implement Z06 A8 cooling on the Z51 instead of making these type of Statements.

robert miller

Then what was the hold back for a few months from GM on the problems it had with the z06 with auto trans in them. Unless them going to a bigger trans cooler & the other one that you are saying about also.

descartesfool

The official response from Tadge about the auto and track use:
https://www.corvetteforum.com/forums...-on-track.html

"The Z06 Automatic transmission put in "Drive" selects the lowest possible gear ratio for best acceleration, and because it has 8 closely-spaced ratios typically runs higher average RPM than the manual. This optimizes lap time performance, but also taxes the engine oil and coolant more for any given track. So the automatic has the capability to run faster laps than the manual, but thermal limitations are reached more quickly. Customers who are planning to run extended track-day sessions at 'professional' speeds, are advised to go with the manual transmission, or to paddle shift the automatic and select higher gears when conditions warrant it."

KRPTONT

Yes it is a Z51, No its not a Z. Temp was 70 Plus. I switched back and forth from auto to manual. I am now planning on wrapping the exhaust. I agree GM should of put the Z06 Transmission Cooler on the Z51 also.

DOUG @ ECS

We suggest to take the trans cooler out of the radiator, add the largest cooler you can add with a fan in front of the condenser, and go enjoy your auto on track. You're trying to cool trans fluid in 200+ degree radiator fluid, physics says "I don't think so".. Your coolant temps will run cooler also.

Should you have to do that with your new car? No, but tracking the car is an extreme condition that warrants additional components such as better brake pads or some cooling help.

We have done this countless times over the years with C5/6 auto's, I cannot see adding a cooler harming your warranty when it's a known problem, but I'm not GM.

Hope that helps.

descartesfool

The transmission cooler is not in the radiator. There is a completely separate transmission cooler in the driver side rear quarter panel for all Z51's and Z06's coupes with the Z06 core being larger. The automatics have a fan fitted to the transmission cooler while the manuals do not. The automatics also have a second transmission cooler loop with fins around the pipes that the manual does not.


The engine oil cooler runs to the radiator core.

mdrums

I've been driving a Porsche PDK since September 2008 and do many track events in Florida and Alabama. Never had a PDK over heat issue...it just works and works well.
Chevy isn't going to out engineer Porsche. I was hoping Chevy A8 was going to be the ticket for the C7 but so far Chevy can't get it right in either the Z51 Vette or Z06 Vette....Z51 Vette engine works great and tranny over heats...Z06 engine over heats and A8 tranny works great....geesh how hard is this to figure out?

DOUG @ ECS

Obviously I have not had anyone with this problem on a C7 yet.

But the point is the same, increase the trans cooling when using it in an extreme condition.

descartesfool

Easier said that done!

5thGear

absolutely true

Jim Barker

I been thinking, and we all know how dangerous that is, about the cooler circuit. Seeing all the ways they try to save horsepower have they reduced the cooler flow in favor of lower pump volume on the trans. Normally the excess oil across the main relief goes to cooler circuit. Has this been changed. Just wondering why all these coolers are not working? More flow, bigger lines needed? My bet is GM knows exactly what it is.