Be careful with which bits go with which transmission, as, depending on the year of the 4l80e, there can be slightly different parts inside. Just swap the tailshaft.
Or you could just put in the other transmission...
2004 GMC Sierra 3500 C&C, added 4WD, 6.0L gas, Extended Cab, SLE, Transgo 4L80e-HD2 kit installed
Whee! Dually Club Member #1109