Friction Modifier Needed?

[ssbullet]

I was told by gm guy that the front n rear diffs need to have a friction modifier added to them when changing fluids. Anyone else heard this?

[The_aSSet]

I don't think this is advised, I used just royal purple gear oil in my rear end and haven't had a problem.

[1BAD2K]

Friction modifier is needed if you use some bullshi!t axle fluid. Use a full synthetic like royal purple or redline like myself and other use and you won't need it. It is meant to bring conventional oil up to synthetic standards from what I've read.

[T-Bag]

No it isn't needed. The Eaton G80 locker calls for a 75-90w synthetic gear oil. No additive needed. There have been many discussions and debates on this. When adding the additive on top of a fully synthetic causes foaming and for it to be actually too lubricative thus not allowing clutch packs to engage causing a one tire fire lol. Royal Purple, Mobil 1, Amsoil or Valvoline.

 

A friction modifier is needed only on a limited slip posi. The SS's and VHO's come factory with a locker.

[zippy]

The additive has nothing to do with using cheap fluid or good fluid. The type of clutch material and locking system used in the Gov-lock that is used in these trucks does not fair well to using the additive. If you add it in the locker will still work, the problem is that it is very good at not un-locking when using the additive which will cause you to get the spool feeling when driving it around. The additive is only make for standard clutch or cone type limited slip diff's where the material in the clutch pack is designed to use it no matter the brand of fluid.