Going to 4.10's tomorrow and decided to put Royal Purple 75W90 back in. It says that it has the limited slip additive already included. Does this mean I don't have to put Ford additive in also.
Thanks
Chris

 

i think that you dont really have to put it back in, its only there supposedly to keep the rearend quite, so no most people say its not needed, unless you put in new clutches (you should soak them in the friction modifier) you shouldnt need any

 

Already contains it. Dont sweat it.

 

I used the 140 for higher temp. I thought it was added insurence.

 

I put Royal Purple in mine without the additive.

I even found a gasket for the cover at NAPA.