I have been experiencing some problems with high rpm shifts with a t56. Not all that high of rpms, like around 5000 to 5200 rpm shifts. Engine does not make power and this is the redline area. Shifting at anything below is fairly normal and somewhat smooth. The harder your are on the throttle the more difficult it is to shift. Gives you a feel that you are fighting the transmission.

The transmission is a GTO t56, I think a 05. Running a stock Corvette clutch and slave cylinder.

The vehicle is a 99 silverado that came with a 5 speed.

I had to replace the clutch pedal after it broke one time. This piece if I remember right comes with the master cylinder as part of the assembly. I cant remember though.

I have had this set up for about 7 years. I originally had a B and M ripper shifter, but wore that out. I recently replace that with a American Powertrain shifter and a Joes shifter handle. This is when I noticed the problem. At first I thought the shifter was not adjusted right. Im from the Munice world and this internal rail is a entirely different feel.

What is the cause of this?

From what I have gathered, the clutch could be worn of course, but I dont think that is what has been going on, could be though.

One interesting thing to note is this. If you drive the truck up on ramps, like to change the oil, the truck does seem to want to stall, not sure if that is even related.

I could not really bleed the slave cylinder. There is no valve that I can see. What I did is basically extract fluid from the cylinder and put new fluid in and work the clutch, working in new fluid. I did this several times, but this did not help.

Seems like several people think the slave cylinder is dirty and needs to be cleaned better or replaced.

Any other ideas or comments?