Rear end lube

[yahrt]

Despite browsing through all of the threads I could find on this topic, I am still not sure how to proceed. I have a Moser 8.8 from FF with ring and pinion from US gear, it states EP85-90 gear lube, nothing about modifier, and came with a tag that read "the replacement of gaskets, seals and filter should be performed before addition of fluid". Questions; (i) should I use friction modifier? (ii) I am assuming I can ignore replacing the gaskets, seals and filter, and simple add the lube to the fill hole, correct? Thanks

[Ducky2009]

I'd say, Yes, add Friction modifiers to lubricant in order to reduce friction and wear. I purchased my rear end for MSP (Mustang Salvage Parts) here in Georgia and they supplied it with the rebuilt rear end. They also recommended Ford lubricant.

[Cobragreg]

If it is a traction lock with clutches you should add friction modifier .. I am running a Strange Rear axle with A Detroit Locker 3.55 gears ...

[boat737]

I have a Moser M9, Ford 9”, Eaton Detroit TruTrak, Differential lube – Motul Gear 300 75W90 synthetic, (per
Moser: Motul synthetic is OK with TruTrak. It does not have friction modifiers like most synthetics.)

[CraigS]

In my old solid axle w/ carbon fiber discs FoMoCo clutch type lim slip I ran Mobil1 80-90 gear oil w/o modifier.