Friction Modifier (non-marauder related)

[ctrlraven]

The girl I have been seeing for awhile has a 1999 Jeep Grand Cherokee. Her dad and I will be replacing an axle bearing and seal sometime next week. The manual says it needs 80w90 gear fluid (she doesn't tow or off-road) so no reason to go to 75w140. But it says friction modifier is needed. Are all friction modifiers the same? Like if I bought a 4oz bottle from Ford could I use that for the Jeep?

May seem like a dumb question but rather not screw something up on her vehicle.

[crouse]

I wouldn't think it would matter, but I'm not sure. Friction modifier is only used in rear ends with limited slip differentials. I suppose it makes sense that a Jeep Grand Cherokee would have a LSD. When I changed my lube, I used Ford's gear lube which was a synthetic. I can't remember if the friction modifier was specific to the synthetic lube?

[fastblackmerc]

I know you don't need friction modifier if using Redline gear oil.

[MOTOWN]

the ford fm will be fine, i used it in my wrangler front, and rear axle.

[ctrlraven]

the ford fm will be fine, i used it in my wrangler front, and rear axle.

That's what I figured since the Dana axle shares the Trac-Lok in some models.

[Marauderjack]

Ford's FM is the best there is......period!!