VTHokie77Vette

I was wondering what oil to use, how much oil, and how much GM posi additive I need to relace the oil in the diff of a '77 with 3.08s. I didn't really want to take off the cover, so I sucked it out with a hand pump. I just wanted to freshen it up a bit. Do I fill it up to the level of the fill plug?

GTR1999

I use 2 bottles of GM limited slip additive,but you can use only 1.
I use 80-90wt gear oil and fill to the bottom of the fill oil. I believe the capacity is 59 oz,but I can only get that in when I have the rear end out on a stand.
Gary

Frank75

I poured about half a quart bottle of lube in then poured one of the additive bottles into the container and shook it up to mix it. Did the same with the other (2 bottles of additive total). This makes it easier to pour. The other thing you might want to do is drive slowly in circles a few times (each direction) to make sure the lube gets between the clutch plates.

Stoge

I was thinking put in both bottles of posi additive and fill rest of the way with the gear oil.

A C

My 69 took almost 2 quarts after rebuild. I didn't put any posi additive in, as the gear lube label said it was already in there. I guess I will see if they are right in a week or two.

Steve Straus

I ended up using Amsoil synthetic diff lube. I've had it in there for about 2 years now and have NO chatter. I didn't end up needing any limited slip lube. It's still quiet too. Their synthetic 80W90 seems to be great stuff.