c6 shifting very weird with fresh rebuild

the trans wont manual shift to 2nd from 1st and when In drive it shifts to 2nd and drive very fast and you can barely feel the shifts. i have tried un pluging the vacuum to the modulator with no change in the shifts and adjusted the modulator all the way in and no change !


trans specs:

fresh rebuild

transgo shift kit stage 2

kevlar band

f lever

stock servo

purple stripe modulator "old"

2600 stall

get a hold of Frank merkel ...he is the c6 king

Is the modulator valve in the case backwards?

Ck your govenor on the tailshaft make sure those valves are not stuck or the springs misssing. I would also ck the valvebody , make sure it is clean and the check balls are in the right spot or make sure the are not missing.

badshoe wrote:Is the modulator valve in the case backwards?

i checked it and it was in right, i ended up taking the modulator apart and took a shim out that i put under the spring and put a black stripe modulator valve in it and it seems to shift ok now. it does shift to drive awfully fast after going to 2nd ! i'm going to adjust on the modulator valve some more and see what happens.

Modulator Apart and shim ??

Some do upshift quick like that . Modulator adjustment may help or one i did i had to go to a longer pin

Gregaust wrote:Modulator Apart and shim ??

Some do upshift quick like that . Modulator adjustment may help or one i did i had to go to a longer pin

I was just going to ask about the pin I have changed types of modulator and had to change the pin to get to shift right.

I have found some modulators do vary. One i did a little while ago, original modulator the pin has a little preload, new one pin was loose. Had to go from 42.3mm pin to 43.3mm

Same thing happend with our car with a c4, it was a combiination of the fluid level being off and the linkage needing to be adjusted.