Does anyone know if the transmission/transfer case electronic system is tied to the engine electronics and ECU? I want to do a 2wd to 4wd conversion on my 2006 Tundra which was in a wreck and was totaled. I don't care about having a salvage title because I will never sell this vehicle anyway. I have a donor 4wd vehicle, with lower milage, that has serious frame rust issues but still runs great. I need to know the ins and outs of the electrical and ECU systems and whether I will have to change all that out, e.g. wire harness, ecu's, etc. Anyone, anyone?