Differential fluid change - do I need friction modifier?

Humvee21 said:

This is what the owner's manual says about the front diff: 1.8L of Motorcraft SAE 80W-90
Premium Rear Axle Lubricant

and for the rear diff: 2.6L of Motorcraft SAE 75W-140
Rear Synthetic Axle

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The Owners Manual Supplement for the 2011 Raptor says the above but adds the following:

Rear axle fluid friction modifier
4 oz. (118 ml)
Additive Friction Modifier
Ford PN: XL-3 EST-M2C118-A


It's on page 24 of the Supplement.
MCR, I think you probably need to come to an understanding of this QUICKLY.

Ruger said:

The Owners Manual Supplement for the 2011 Raptor says the above but adds the following:

Rear axle fluid friction modifier
4 oz. (118 ml)
Additive Friction Modifier
Ford PN: XL-3 EST-M2C118-A


It's on page 24 of the Supplement.
MCR, I think you probably need to come to an understanding of this QUICKLY.

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It's 6 degrees outside anyway. Won't be changing it today. Yeah it'd be nice to get a def answer on the friction modifier.

^ Oh you big chicken! Put on your woolies and go freeze your ass!

Yeah, just kidding. It would take forever for the pumkin to drain and to refill it at those temperatures.

MCR, if you have the factory cover on your differential, how do you figure to refill it? If I remember right, the factory cover has a drain but no filler.

Sub'd.

Ruger said:

The Owners Manual Supplement for the 2011 Raptor says the above but adds the following:

Rear axle fluid friction modifier
4 oz. (118 ml)
Additive Friction Modifier
Ford PN: XL-3 EST-M2C118-A


It's on page 24 of the Supplement.
MCR, I think you probably need to come to an understanding of this QUICKLY.

Click to expand...

You are absolutely correct. Here's the fineprint to the capacities page:

4* Service refill capacity is determined by filling the axle to 1/4-9/16 inch (6-14 mm) below the
bottom of the filler hole with the vehicle on a level surface.
Add 4 oz. (118 ml) of Additive Friction Modifier XL-3 or equivalent meeting Ford specification
EST-M2C118-A, for complete fill of 8.8 inch Traction-Lok axles.

5*Your vehicle’s rear axle is filled with a synthetic rear axle lubricant and is considered lubricated
for life. These lubricants do not need to be checked or changed unless a leak is suspected, service
is required or the axle assembly has been submerged in water. The axle lubricant should be
changed any time the rear axle has been submerged in water.

So they're saying that you never have to change your rear diff fluid?

etalian2005 said:

So they're saying that you never have to change your rear diff fluid?

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Yes, and of course you don't need to change motor oil but once every 15,000 miles, too. In other words, only if you care nothing about your supertruck.

Yeah I did some deep ass water crossings last fall so I might have some contamination. Just being on the safe side.

Gollas108 said:

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10/10 quality post

would read again

Gollas108 said:

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Somebody ban this twit.