friction modifier for mobil1 in differential

[bwinterroth]

Do I need to use friction modifier if I want to put mobil1 75W-90 in the real differential? Thanks

 

[aldive]

When I used Mobil 1 in the rear, I never used a friction modifier, nor do I with the Amsoil that I currently use.

 

[aldive]

I found this on an Amsoil website ....

The best way to determine if a friction modifier is required is to, after installing the synthetic gear lube in a limed slip axle, go out and drive the vehicle as you normally would but also be sure to make several tight right and left turns, or find a location where you can safely and slowly drive in a figure “8” pattern for a minimum of eight to ten repetitions. If you notice any chatter on turns then you most likely need a friction modifier and you can take out the differential filler plug and add it very easily. If you do not get any chatter then you do not need friction modifier.

 

[ExplorerDMB]

I'll say this, but it is not to be taken as 100% true for all synthetics; but most synthetic gear lubes already have friction modifier within it.

-Drew

 

[snocross1985]

friction modifier is not needed when using mobil 1 in the diffs.

 

[celly]

What would happen if you use friction modifier anyhow with Amsoil? Can it hurt anything? Amsoil seems to recommend it for my application (at least when I enter my year and engine into their online application). Then again, they tell me to use 5w/20 in the crankcase when Ford says 5w/30.

 

[ExplorerDMB]

You might have a different oil viscosity because of where you are. Most Fords and Hondas now run on 5w-20. GM is still on 5w-30. Anyway, adding friction modifier to synthetic fluid would (in my opinion) not do a thing. Just take more money out of your wallet. Might just extend the life of the friction modifier. Not exactly sure. It may hurt it cause I don't know what type of viscosity the modifier is - if it isn't the same rating as the 75-90 or whatver weight you use and then you put extra modifier in there that isn't rated for extremely high heat (although you think it would with the clutch packs and that type of friction), but then it would be like running low on gear lube and you may hurt your gears. However, I doubt that would happen. Woah - that was a long sentence.

-Drew

 

[celly]

5w/20 recommendation is at Amsoil and is not related to my geographic location. I'll probably stick with 5/30 especially since I can source it at a local auto parts store.

Thanks for your take on the modifier. I'll probably pass on it.

 

[Runnin'OnEmpty]

According to Mobil, FM isn't normally needed in their synthetic gear oil:

http://www.mobiloil.com/USA-English/MotorOil/Other_Products/Mobil_1_Fully_Synthetic_Gear_Lube_75W-90LS.aspx