I agree with Walt. I used the same as he suggests in my GS.
When I had my Ford 1 ton serviced, the dealer didn't have the Ford additive in stock, so they used another brand. It caused a chatter in the rear when turning. I changed it to the Ford additive , chatter gone.
I incurred the same thing with a Blazer I had. Made the mistake of using a non GM additive. Again chatter untill I corrected it with the GM additive.
Like Walt suggested, use a top quality gear lube and the GM additive.
Loren