if you still have the transfer case, you could slap the 4wd transmission and transfer case into your 2wd truck pretty easily. You'd just need the driveshaft from the 4wd truck. Only thing I see a problem with is cutting your floorboard out for the transfer case shifter. Would be pretty cool, you'd have a double underdrive granny gear! haha! Probably wouldn't hurt to grab the crossmember from the 4wd truck, just to be safe, but I think they utilize the same one.
If you don't have the transfer case, then I'm not sure it'd work, unless you have a slip joint in the driveshaft itself, since the 4wd sm465 is a fixed rear yoke.