rear end fluid
If you go to the local autoparts store, you will see several brands. You need 2 quarts of fluid. If you buy dinosaur fluid, you will need the additive, which your local auto store also carries. If you buy synthetic, it usually has the additive already in there. I use Royal Purple synthentic myself, but most of the brands are fine. You will need the 85w-90, btw. Also change the gasket while you are there.

