I have an aftermarket solution with a custom plug-and-play harness and custom program for the PCS 4L80 TCM that lets it work in harmony with 01-05 Duramax ECM's...IE, Im able to get the 4L80 TCM to communicate via J1939 CAN with the 01-05 Duramax's for all of the necessary throttle/boost/temperature info, as well as defuel....although defueling has not been fully tuned yet.
Its a little more expensive than running a cheaper, more basic 4L80 controller totally separately from the Duramax ECM....but its definitely the nicer, more complete and seamless option. :thumb:
For 2006+ 4L80 swaps, just use the factory T42 with a modified Express van calibration.
Ben