Most dealer parts departments (Ford, Chevy, Mopar, etc.) sell a 6-ounce bottle of limited slip additive that seems to be generic regardless of whose name is on it. I don't think I've ever seen a similar product at the FLAPS stores. Add it to the lube in the rear end and if the cone clutches are the source of the drag or chatter, it usually cures the problem.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!