I just did the head gaskets on my 01 SS, I immediately started getting all types of transmission codes. I brought it to a shop that checked it for free. They confirmed that there was no power whatsoever going to the harness that goes into the trans.. Any ideas where I should start looking? He told me to splice a wire to the pink/power wire and run it to the trans fuse. I did that and it worked, but I don't plan on leaving it like that.

 

IIRC,pink is always a "hot in run" wire. My guess is to start with the pink wire at the harness and work back. Somewhere,it might have gotten cut,hence no power.