My biggest concern with swapping rear ends would be making sure the one you put in it is in better shape that what it replaces. Most of the replacements you get are also going to be around 30 years old as well.. The job itself is not that technical, more labor than anything.. tight old bolts that are often rusty.. and large heavy parts... Last few I've changed.. I just break the u-bold off; disconnect your parking brake cables, Hydraulic brake lines, and rear u-joint.. Not in that order. Do the U-Bolts last. And be sure you have your replacement first.. You'll want to make sure it is the same differential ( for speed and convenience) D44 for D44, 8.75 for 8.75, etc.. Verify they use the same U-joint.. I've done them in parking lots in a couple hours, and had them fight all the way through before..