MAILORDERTUNER.COM: ECM / TCM

Only The Gen 3 ECM has a built in TCM. Anytime changes are made for stall, tire size, and shift points: Mailordertuner.com will need a TCM. 2007+ T42 TCM can be found behind the PCM 6l80/6l90, the TCM is found inside of the transmission. You will have to remove the valve body in order to access the TCM so it can be sent in.