Quote:
Originally Posted by GA_ZL1
I had a GM tech do a ATF change recently on my 2023 ZLE A10 after the recommended 15 hours of track driving. The next time on track (yesterday at Road Atlanta--it was hot), I started getting some funky shifting, which makes me wonder if the bleed was done correctly.....
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I finally was able to get a hold of a PC and download the Cosworth software. The
first screen shot shows data from an
early PM session last Sunday at Rd Atlanta when I had the funky shifting. The
second screen shot shows data from an early
PM session at Rd Atlanta in April. Note: The
April session had the original factory AFT fill; the May session was after my recent AFT drain and refill. Now, the ambient temps were different on the dates (mid/upper 70s in April; about 90 and more humid in May), so I don't know how valid comparisons can be, but clearly the maximum AFT was hotter this past weekend (244 degrees F vs. 225 degrees F) when I had shifting problems. Also max water temp was hotter (246 vs 225), as was the max oil temp (298 vs 286). Man, these cars with the A10 run hot! However, these data tell us nothing about the
volume of AFT in the system. Given these data and caveats, perhaps someone has insight into the two sets of data? I tend to agree that the AFT was probably overfilled when changed between the two track dates. I'm going to take the car back and have the tech recheck the AFT and bleed off excess fluid.
Does anyone know the target AFT temp one should try to achieve before doing the bleed? Is that in the 2023 ZL1 1LE Service Manual perhaps? Thanks for everyone's input and help!