Sierra4l80

Thank for your response, I was going crazy looking for a separate tcm. I’ve pretty much scoured the internet looking for fixes for this for the past month. At this point im convinced it has to be electrical. I actually tried 2 converters thinking the rebuilt one I bought might have been a dud. It doesn’t throw any other codes. I took the computer out and cleaned all of the connections to no avail so im starting to think there’s an issue in the wiring where the tcc pwm is getting just enough power to not throw a code but also not enough to get a full lockup. I’m at loss at this point man the trans has been out twice and I’ve dropped the valvebody 3 separate times so I’m grasping at straws.

2006 Sierra 2500hd 2wd wt, 6.0/4l80e. Po894 code. Fully rebuilt trans and replaced all valves/solenoids/bushings that can cause this code, tcc still has 150-200 rpm of slip at full lockup. Beginning to think it’s a connection issue. Going to start testing but literally cannot locate the tcm on this truck. Looking up replacements shows a small silver box and I know on the duramax the tcm is located on the radiator shroud. The only modules I can find are the ecu under the battery and the throttle module on the firewall. Is the tcm integrated with the pcm on this model? What am I missing here? Thanks