Hi all,
So I am about to change my gearbox & diff oil.... In the past I have used friction modifier's like Slick 50 as an additive to the gearbox.....has anyone have any opinions on this or should I just use the standard recommended gearbox oil ?

 

If you have to add an additive to your oil, you picked the wrong oil to begin with

Just use the normal recommendations. Mazda's oil, Redline, or Eunos. Avoid Royal Purple unless you like replacing expensive parts.