Did a difflock rear end swap yesterday. Out of a DB51T into another DB51T. All went well. We used the factory difflock switch but got no response. We determined that the 4WD controller did not have the circuitry to run the difflock, although the truck was wired. Swapped 4WD controller and all was well. On the flip side, you could simply wire up an aftermarket toggle switch to engage the difflock if you aren't using the factory parts. Just an FYI for anyone else attempting this swap-a-roo.