OkeeGuy

im sure this has been addressed here before so i appologize for asking...but,
what kind is the best?
how much of it?

GTR1999

I like to use the GM stuff both the additive and the dino oil. Use 2 bottles of the additive and fill the housing until the oil is weeping out the fill hole-about 2 qts if empty.Be sure the rear end is level.
Gary

vettfixr

i would recommend using the GM additive. When I did my rear i used gear oil that said it ws good for posi's but within the first week or two it started making clunking noises. I put in two bottles of the GM additive (I think they were 8 oz. each) and haven't had a problem since. When you put the additive in go to an empty parking lot and do some figure 8's to work it in. It's been quite a few years since I did mine and everything's been fine so far. Good luck.

Eddie 70

I too used the GM stuff in the 70. When I had my 79, I put the Mobil 1 stuff in there. Both work great.

Wrencher

I use Redline HD synthetic gear lube in all my applications, both transmissions and differentials with excellent results. A bit pricey, but effective.

Hans

pws69

I used 1 bottle of the GM additive and filled it up with Mobil 1 gear lube. No problems at all. Some say 2 bottles of the GM goo, but I didn't find that necessary so why waste it.

Barry's70LT1

I used one bottle of GM additive and filled with GM diff oil.
That was two years ago. No problems yet...

Sleper

Two bottles of GM additive and gear oil. My $0.02 :cheers:

gliot1

The directions on the GM bottle and GM shop manual said (1).