Look for evidence of leaky rear axle seals. You'll see gear lube that has leaked out onto the rear wheels (star pattern from the middle of the wheels). It's not a show stopper, but tells you that new rear axle seals are needed, plus maybe new rear brake pads and bearings. If you can do the work yourself it's pretty cheap to fix to simply replace the axle seals. But on mine at around 50K miles, I had to have all four new rear axle seals, new brake pads, and new bearings installed by a knowledgeable shop. As I understand it, the bearings have to be pressed into place on the axle. It cost me about $500 for everything on the complete rear axle rebuild. A lot of 3rd gens here have had problems with the rear axle seals.