I do not believe that Fiat-Chrysler or GM or Ford manufacture their own. They are probably all made by the same chemical company like CRC, which uses K&W as a brand name for their friction modifier for limited slip differentials.

Most of the parts in an automobile are made by suppliers. I see no reason to believe that the goop that they sell is made by the "car manufacturers" either. MAYBE it is made to their specification by a supplier. And maybe the supplier gets their specification and comes back with a bid, but says "if we could substitute this we could save you 17%" and so what you buy in a Mopar or Motorcraft or Delco can is actually the same stuff.

R.