I got a 99 with 3:73 gears. Today I put in 2 quarts of royal purple 85W -- something or other and I dont believe it filled it up all the way. Anybody know if I need more? Is the oil I used fine? Thanks in advance...

 

You want to fill it until it is just below the fill hole...like 1/4 inch or something. Or you can just fill it until it runs out and let it run out until it drips, then install the plug. What I've done in the past is to use an allen wrench, the kind that's shaped like an L, and put the short part into the fill hole to check the level...when the gear oil is about 1/4 in. away from the top I know I'm good.

Your rear calls for 75w-90 synthetic gear oil, personally that's what I'd stick with.