Litl T&A

Need to know what kind of fluid to use on rear end of a 98 Trans Am (LS1) Want to use synthetic -Royal Purple-.....What type of fluid did the LS1 Trans Am have from the factory? And how many quarts does hold?
Thanks

01ssreda4

iTrader: (96)

Any synthetic with posi additive already in it will work.

Any standard oil with you adding a separate posi additive will work.

Holds approx. 2 quarts.

Litl T&A

What Viscosity?

mjs1012

iTrader: (36)

I use non synthetic 80w90 with a bottle of gm additive.

demonspeed

iTrader: (7)

Correct me if I'm wrong, but I believe we've hashed out a lot of stuff here about 98 and older not using synthetic because it's a clutch-pack style differential (and for whatever reason it not liking synthetic even with the additive).

Chevyman1968

I changed the fluid in mine this weekend and i used Lucas. No complaints yet.

Litl T&A

So synthetic or not? Just bought some Royal Purple synthetic....

Blackpanther99

iTrader: (8)

Thats a good point, I have read the samething before. Even though I do believe GM recommends synthetic oil, I would read the owners book first.

Chevyman1968

Regular Ole Lucas.

01ssreda4

iTrader: (96)

Just use what you got. If it gives you issues then you can change it out. I think its just hit or miss. I use 75/90.