New TCI Streetfighter won‘t shift in 3rd when hot

CudaFactHackJob said

Did you get that Total Crap Inside removed from the vehicle yet??

Click to expand...

No but I thought about switching valve bodies…

Would the original 904 valve body (which worked in my old trans) fit?
I studied the original service manual and I am going to try this next.

Btw. I adjusted the kickdown cable by the book and installed the recommended bracket.
That can‘t be the problem anymore.