i need some advice i have a 1985 f250 ford with a 460 it has a dana 70 rear diff with a power lock slimted slip it is raising hell with a trailer behind it or when you turn i changed the oil in it not long ago with reg old gear oil and put 2 tubes of bg ls2 limited slip friction modifer do i need to use a syn oil with a diffrent type of limited slip addivite or what its real loud grinding noise (chatter) when turning with the trailer thanks alot 
