I have always thought the Friction Modifyer is to somehow make the clutches work so it actually modifies the friction qualities of the lubricant. Since we that have limited slip type axles could use some additive that is a lube enhancer to help with heat and/or slickiness of the lube. Something like Marvell or TufOil.

 

I personally wouldn't. It doesn't call for it, and I very rarely have ever heard of anyone having issues with there rear ends.

 

I also agree. I wouldn't use a friction modifier, really no need to for the AAM 11.5s unless you have some binding issues, and that is normally due to those that were putting heavy weight oil in the diffs. Dodge calls for 75W-90 weight GL-5 syn, NO friction modifier. I'd just stick with that...

 

There are no clutches in our limited slips, which is why there is no need for the modifier.