the gasket for the rear of trannies to the hoising assy-ext of the 2wd and the adaptor that go to the T/C are the same gasket so that means same mounting, the drive shaft I beleave is 2pc on the 2wd with a u-joint in the middle, the 4wd is not,

So if you have a 2wd tranny and wanted to put it in a 4wd from the bellhousing to the rear of the tranny minus the cone would fit a 4wd but would need a rear cone to the T/C and a different driveshaft, same goes for a 4wd to a 2wd a different driveshaft, remove T/C and different cone, but would need the center support for the 2wd driveshaft, one thing if going to a 2wd from 4wd make sure the center support bracket is welded to the frame on the truck, to know what I mean you would need to look under both a 2wd and a 4wd to look at the center support.

hope this helps, John