LS 2 stuck in limp mode in my 55 wagon

[john olsen]

HELP i just installed a 06 gto LS2 and 4l60 trans in my 55 using gto harness car runs but check eng lite on code co101 [transmission not communicating] drove donor car before removal ran fine had pcm and tcm flashed. car runs but has zero power and is in 2 nd gear through which wire or wires does the tcm talk to pcm what may i have messed up in wiring in gto harness and leads for help appreciated im in ca la area

[WagonCrazy]

if you can get your hands on an 06 GTO wiring diagram, that might give you some clues as to where to start checking (pcm and tcm wiring).
Not sure what else to advise at this point.

[Rick_L]

Unless you find something obvious, like a missing or broken wire or a pushed terminal in a connector, you are probably going to need to put a scanner on it to see what is happening real time.

[Old Buzzard]

Update?