NHRATA01

iTrader: (10)

Ok, I'm about to change out the fluid in my new 12 bolt now that 500 miles have past and break in should be about complete. Also the Eaton was chattering a bit on tight turns, and I wasn't sure if the additive was used when it was installed. Anyways I bought some Castrol 80-90 gear oil, which said for limited slip use. On the back, a label said it meets a certain GM standard for limited slip units, and doesn't require an additive. Now, I also have a tube of the friction modifier on hand. So should I used the additive or not? I was actually just trying to find some conventional gear oil and then just add the modifier without question, but the only non-synthetic they had was the Castrol and Lucas (also said for limited slip use). Any ideas? Thanks!