For a couple months, I had been dealing with a horrendous clunking noise coming from the rear axle every time I put it into reverse, or if I went to a forward moving gear from reverse. Finally figured out what it was though, the rear differential bushings were completely destroyed.
Found a couple of forum threads discussing fixes for similar problems, and discovered one that describes using polyurethane window adhesive (common brand: 3M’s WindoWeld) to stiffen things up. Sure enough, it worked. Jacked up the diff to level out the bushings, squeezed in a good amount of goop into the remaining areas, and let it sit for a day or so. When I set it back down, fired it up, and drove it around, it worked way better than it did. Not bad for a $25 fix. Labor for a true factory fix would have been horrendous.