Using gear oil "for posi", additive still needed?
#1
Using gear oil "for posi", additive still needed?
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!