How hard is a 6L80E swap into a 2008 Silverado 4.8/4L65E 4wd using a 2010 5.3/6L80E donor?

Here is what the documentation says. Each point links to its source; details depend on your exact computer, harness and transmission.

• PSI's instructions require sending the removed T43 module along with the transmission's four-character ID tag, where the first character identifies the model year. (D9I5Ve8F04Qxt)
• On 6L80E swaps the TCM sits inside the transmission, so factory wiring and harness connections clip back into place with no special external controller. (LSX Magazine)

Confirm against the instructions for your exact parts before wiring. More: Transmission control in our tuning guide.