Dj_poop

Looking to replace differential fluids in my 2010 f150. Dealership wants $35 a quart for the diff fluid. I can get royal purple for $21 a quart but it has the friction modifier already and I don't need it seeings how I have a electronic locking rear diff. My question is will buying the rp with the modifier already affect the diff? Also anyone know a good brand of transfer case fluid or should I just stick with the Motorcraft?

PerryB

There is no harm in using friction modifier when its not called for. As far as the T-case, I think it calls for ATF although I don't recall which flavor (V, LV, etc). Assuming its a conventional gearbox and doesn't have any type of a clutch mechanism like some AWD's use, I don't think it really matters.

Tones

Mobil 1

lilspeedy626

Yes you'll be okay. I use the same kind of oil for my differential.

crazydubc

I used this. I also have lockers. Easy to do yourself on the rear...front is another story. On the front you are better pulling the entire diff and having a drain plug added.

https://www.amazon.com/Royal-Purple-...dp/B000J15THO/