[maxpower]

97 F350, 4WD. Going to change out the axle fluids. Wondering which brands you use and does that brand need the friction modifier? I'm reading that some of the synthetic brands don't need it but am wondering which ones those are.

 

[tjctransport]

regular old 90 weight gear oil with added friction modifier.

 

[Whoknows]

I run Lucas 85w-140. Talked with the guys at East Coast Gear Supply and that’s what they recommend.


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[Lt.Dan]

Valvoline 75w140 here. No friction modifier as its already in it. TrakLok works perfect.

 

[Bugman]

A couple of things, if you don't have a limited slip rear end you don't need the friction modifier.

Most synthetic rear end oils already have the modifier in them, look for the GL-4 or higher rating on the bottle.

I use Valvoline Synthetic 75w-140 in mine also but I have a open rear so I don't care if it has the friction modifier in it.

 

[JCart]

This front and rear in all my trucks and Honda Pioneer 500 differentials. Heavy ShockProof®