i just bought 2 quarts of royal purple 75w 90 gear oil and a bottle of ford racing friction modifier. i had put all of it in my rear end i just read on the royal purple bottle that it already contained a friction modifier. am i still ok to run both in my rear end?
Brands like Royal Purple have friction modifier in them already and don't need it added, but adding extra won't hurt either. Again whether you need a friction modifier in the first place depends if you have a clutch pack based differential in the back, lockers, helical types don't need it.
Brands like Royal Purple have friction modifier in them already and don't need it added, but adding extra won't hurt either. Again whether you need a friction modifier in the first place depends if you have a clutch pack based differential in the back, lockers, helical types don't need it.