a guy i know recently wrecked his truck which was a lly and wants to sell his trans that is already built to the hilt but his truck is an 05 mine is an 03 will this work?

I'm told that all you need to change is the fittings on the tranny that the cooler lines connect to. I'm not 100% of that but I've been told that a lot of times.

I'm thinking of doing the same thing. Wouldnt the tcm need changed as well?

I'm thinking of doing the same thing. Wouldnt the tcm need changed as well?
GM only builds the '05 as a replacement for all 5 speeds. '03 may or may not need the cooler line adapters for fitment.

the only difference is an extra solenoid in the valvebody.

the only difference is an extra solenoid in the valvebody.

The '01 through '04 LB7 TCM are not looking for the G solenoid so that is not an issue with the TCM. Fittings are different as they changed sometime in '03. I have the adapters to fit the '05 into the early Ali. They are cheap. call me if you need them.