does anyone know how much fluid is required for the diff, and how much friction modifier to add? also are there any brands that are better than others? i bought Mobil 1 75w 90 oil, but i'm just not sure what to do about the friction modifier.
thanks for any imput

thanks for the help, turns out the mobil 1 already has modifier added

no problem. if you feel it slipping when it shouldn't, you can add small amounts (too much is bad) of ford friction modifier to tighten it up.

no slipping yet, but thanks for the advice