[rrrocketman]

I have a 2011 impala with the 3.9 and the 4t65e trans in it. I tried to get it dynoed and 2 different guys said it wouldn't work because the auto trans would downshift. That said, I had a grand am a while back with 3.4 4t45e combo and that dyno'd fine but I don't know what the trick was then.

What is the correct procedure for dyno'ing an automatic and specifically with the 4t65e (since transmissions may differ) ?

Thanks!