What oil/posi additive do I use???

I am going to change the diff fluid in my 3:42 posi. What type of oil do I need? Also, I'm sure I will need some type of posi additive. What do I need? What is the best stuff to use on the street?

 

I would get the GM posi additive. There is debate about the oil. Some mauf of rears say do use synthentic but the syn. oil manuf . say it is Ok.

 

Thanks Jim. So, what are YOU going to use when your X is done? :Brow:

 

Factory speced oil with the GM posi additive.

(Brad tipped me that Duane checks for that in Concours)