issus with my 6l90

ok so yes I am new to the tunning side and this style of a swap.
I bought a 2008 Silverado with no motor and bad trans (no reverse or some crap). So I bought a 6.0l with a 6l90 from a 2015 van with next to nothing for mileage. TCM will not talk due to the gen difference, the newer tranny has two more wires than the old one. I have the ECU from the truck and the van it runs great but limp mode only. what is my best course of action, harness and computer swap or just use the older trans valve body with its older TCM?


Thanks in advance any info is helpful.

ps, I do not have the BCM of the van either so I will need to marry the new ECU to it if I swap the harness and ECU out for the 2015 model. (correct?)

The easiest would be to put the 2008 tcm and valve body in the 2015 trans. To the best of my knowledge it is a direct swap. The valve bodies changed i know around 14', who knows when else, but the trans is still the same aside from internal upgrades

Thank you. mbray01.

it works great Now. so thanks again.