81 rear diff
Thread Starter
Intermediate
Joined: Oct 2014
Posts: 44
Likes: 0
81 rear diff
Hey everyone gonna change the rear diff fluid in my 81, I've seen a lot of debating on different weight oil and if u should or shouldn't use friction additive, does anyone know what weight oil the car came with and if they originally had additive in them?
Safety Car
Joined: Dec 2012
Posts: 3,814
Likes: 1,723
From: Summerville SC
I just went to one of the vendors and bought the kit, 2 qts of the correct oil and the friction additive. Might be able to save some $$ going on your own path here, but for how ofter this gets changed I didn't think it was worth the trouble hunting around. Especially with all the other STUFF that my car needs. Just my $.02
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
All of the "limited slip" rear ends require the friction modifier or they'll make a pop pop pop pop pop pop noise when turning corners. The C3's need 6 ounces of a friction modifier as well as a bit under 2 quarts of any good 85W90 hypoid gear oil.
