Hey all I have a C6 transmission that I got from a guy that I was told it had been rebuilt but not ran yet. I stuck it in and it revs pretty high before it shifts out of first which i think is a modulator adjustment, but when you come to a stop it doesnt shift down into first. It just stays in second. When you manually shift it, it shifts fine and it doesnt slip at all or anything. Any help would be much appreciated. Thanks

 

My first guess would be a problem with the governor. Maybe the weights are stuck. That would account for the high shift and no downshift.
The governor is mounted on the output shaft, inside the tailshaft housing.

 

Sweet that is kind of what we were thinking I think we're gonna tear into it tonight thanks ill post up what we find