Sae 90 gear oil?
 

For the rear differential on on 95 4runner 4x4, the FSM says:

Is "SAE 90" a specialty oil I have to order from somewhere ? I can find 80W-90 gear oil easily, but I do not live in Alaska. I used that to top off what I have now, before I re-do the rear wheel bearings. I wanted to put the right stuff in.

Any that are GL-5 and have '90' on the end will do. Older lubes were suited for more narrow temp ranges; thus 90 weight. While more modern lubes are made such that they can exhibit the good characteristics
of a thinner oil while at low temperatures and still have the body that is needed at high temps. Don't worry.

It looks like "GL-5" is MARINE grade oil. I just put some Wally-Mart super-tech 80w-90 in. Gee whiz, good thing I am re-doing the bearings and it's not going to be in there for long.