You don't need anything in the front for sure , it's an open diff . The rear I never put it back in unless I get some chatter but you shouldn't need it . Just put the Royal purple in and drive it . If on sharp turns you feel the rear end "popping or chattering" then add the friction modifier . If you add the modifier get it from Ford , the other brands don't seem to work . Just so you the modifier is only to allow the clutches to slip . This is only for sharp turns . It does nothing else .
Last edited by Bad Night; 05-01-2011 at 07:49 PM.