I just put in another 460 & C6. I am running a 410 9" posi. The motor & trans were just rebuilt before a viaduct peeled the top off the box truck they were in. A friend sold them to me, so I wouldn't have to rebuild my motor.
Problem: I couldn't be happier with my motor. But my tranny winds out at about 60 mph. Of course I can get there in about 4 seconds. The vacum is hooked up, and it is the same rearend I've been using. It shifts twice just like the last 4 or 5 C6's I've had in it over the last several yrs. Except it is wound tight. Everyone who rides in it says something like "is this thing going to ever shift?"
I can't even take it on the interstate.
I checked & all the imfo. says all c6's have the same high gear ratio. 1-1
Any input would greatly appreciated.
Thanks in advance.
1%er

 

Did you check the modulator for available vacuum, apply/pull a vacuum on the valve, or any trans fluid in the line coming off the valve when pulled?