i have a 2008 gmc sierra that is a 6.2/6L80e swap. i have the tow/haul mode through the transmission but i do not have the TU/TD option. i have yet to figure that out past the wiring that is already installed in my truck. basically id have to have the BCM reflashed with a different vin and id have the wrong vin for onstar i think. id settle for my Tow/Haul mode to engage 2nd gear at a low roll vs having TU/TD, then have it shift through the gears like normal at WOT. has anyone done this with the 6L80e yet?
thanks