Differential fluid question

[Craig 2000 TA]

Hey guys... going to be changing my differential fluid soon. I have a 2000 Trans Am NOT ws6 with a stock 10 bolt. I'll probably stick with Mobil 1 or GM products for the fluid...just wonderring if I need any addatives. I know there were two Posi units depending on options and note sure of which I have etc. I just got the Summit Differential cover with a stud kit so I will need to drain it and fill it anyway

So... Mobil 1...what grade oil?
Better to run just GM stock replacement?
How do I know which posi I have and therefore wether I need the addative? thanks in advance for the help.

[N20LT4Bird]

I think they all take the GM limitied slip additive.

[Craig 2000 TA]

Thanks for the input N20LT4Bird.....anyone else have any thoughts on the subject? I wanna protect my glass fragile rear!


errr.. damn that didnt come out right but its to funny to edit out!

[Dave M]

use Mobil 1... 75W-90 I believe it is. It should say in your owners manual or a repair manual if you have one. Get 1 container of limited slip additive and add that also (per the owners manual).

[Rob]

I run Mobil 1 in all the rear diffs I have owned for the last 15 years. None of them ever took the additive. It was not needed.

For performance, the additive hurts performance. Makes it too slick. Go to the track and watch all the one wheeled burnouts. Then ask the owner if they use the additive. The additive is purely cosmetic. People don't like chattering so they add the additive to get rid of it.