Got a few questions I need help with figuring out, i blew up the trans in my 01 and found a fairly cheap 06 tranny im getting this weekend, having the same guy im buying the trans from flash the TCM to a 6 speed but my question is what else do i have to do i.e modifying the wiring harness to work with the transmission correctly. From what i understand im able to take an lly internal wiring harness and put it in the 06 tranny, then manually wire that back to the tcm to plug into one of the pins to get Solenoid G to work correctly, ill also have to figure out how to get the NSBU switch to work correctly.

(this is not a valve body swap, its an entire transmission swap)

2001 GMC sierra 3500 lb7 dually
2006 allison 1000 from an LBZ