Rear differential fluid change?

[rollinstone]

The owners manual for my 2014 LTD says the rear diff fluid is synthetic and no need to change the fluid for the lifetime of the vehicle...unless there's an obvious leak or the axle was driven under water. I've got neither of those.

I mentioned this to my mechanic and he said yeah he knows what Ford says, but if it was his truck, he'd change it. It's approaching 62,000 and I'm doing overall fluids changes...but holding off on the rear diff.

Probably can't hurt, but it's another $100 bucks! Thoughts?

 

[Motorcity muscle]

Would not even consider changing if it hasn't been under water, till at least 100,000 miles. Even on the the old gear oil they did not recommend changing it.

 

[justinp16ex]

Owners manual says it's good, but 100k is a lot of miles for a gear oil. Changing the fluid is much cheaper than changing diff parts. "Lifetime"fluid, but changing them more often will likely increase that lifetime.

 

[Plati]

The owners manual for my 2014 LTD says the rear diff fluid is synthetic and no need to change the fluid for the lifetime of the vehicle...unless there's an obvious leak or the axle was driven under water. I've got neither of those.

I mentioned this to my mechanic and he said yeah he knows what Ford says, but if it was his truck, he'd change it. It's approaching 62,000 and I'm doing overall fluids changes...but holding off on the rear diff.

Probably can't hurt, but it's another $100 bucks! Thoughts?

Where does it say that?
My 2014 owners manual says change every 150000 miles
.. but they call it "rear axle fluid" so is that the diff?
(I'm gonna do all 4 at 110,000)


and WTH is an accessory drive belt(s) ... serpentine?

 

[mnachreiner86]

Where does it say that?
My 2014 owners manual says change every 150000 miles
.. but they call it "rear axle fluid" so is that the diff?
(I'm gonna do all 4 at 110,000)
View attachment 40541

and WTH is an accessory drive belt(s) ... serpentine?

Yes


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[mnachreiner86]

62k miles I personally wouldn’t be in a hurry to change it but it depends what kind of life if it’s lead. If you know the history and it’s been babied I wouldn’t do any of those yet. If you’ve been hard on it, change everything. If you don’t know, change everything. Pretty much everybody agrees hat the lifetime or 150k mile stuff is bogus. If you’re changing everything else I would do rear diff right along with it, it works hard.


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[mnachreiner86]

Also for that price tag get yourself a little pump and do everything yourself, it’s all just drain and fill.


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[07navi]

Stickler.......yes and yes

 

[07navi]

The diff has synthetic in it, it's not like the old days and water and leaks are what kills rear ends. (pumpkins, bangos, diffs, rear ends, third members) .......old mechanics know this stuff.

 

[rollinstone]

Where does it say that?
My 2014 owners manual says change every 150000 miles
.. but they call it "rear axle fluid" so is that the diff?
(I'm gonna do all 4 at 110,000)
View attachment 40541

and WTH is an accessory drive belt(s) ... serpentine?

Page 500 of my 2014 manual says the same thing. However, on page 340 it says "Your vehicle's rear axle is filled with a synthetic rear axle lubricant and is considered lubricated for life. These lubricants are not to be checked or changed unless a leak is suspected, service is required, or the axle has been submerged in water."

I think I found where I messed up...unless service is required...I missed that. So, service is required on the rear diff at 150,000 miles, which I guess is Ford's definition of "life.". So, when it gets to 150,000 I'll change it. Thanks for motivating me to go back into the manual and take a look.

FWIW, I just had the front diff passenger side axle seal replaced today...pesky seep. We checked the diff fluid and it is a really dark/black and well-used color...not healthy looking at all. Will be changing that out right away. Odd, though...because I have hardly ever driven the truck in 4WD...not even 5-6 miles on snow and once up a steepish muddy track...although it had about 28,000 on it when I bought it...maybe previous owner?? Truck was immaculate when I purchased it.

 

[jkayca]

Page 500 of my 2014 manual says the same thing. However, on page 340 it says "Your vehicle's rear axle is filled with a synthetic rear axle lubricant and is considered lubricated for life. These lubricants are not to be checked or changed unless a leak is suspected, service is required, or the axle has been submerged in water."

I think I found where I messed up...unless service is required...I missed that. So, service is required on the rear diff at 150,000 miles, which I guess is Ford's definition of "life.". So, when it gets to 150,000 I'll change it. Thanks for motivating me to go back into the manual and take a look.

FWIW, I just had the front diff passenger side axle seal replaced today...pesky seep. We checked the diff fluid and it is a really dark/black and well-used color...not healthy looking at all. Will be changing that out right away. Odd, though...because I have hardly ever driven the truck in 4WD...not even 5-6 miles on snow and once up a steepish muddy track...although it had about 28,000 on it when I bought it...maybe previous owner?? Truck was immaculate when I purchased it.

Rear diff is always in use. I think you maybe thinking of the transfer case. I don't know if the two are in the same unit on the Expedition and therefore share gear oil. Either way, the fluid in the rear diff is going to get used even in 2 wheel mode as the Expedition is rear wheel drive when in 2 wheel mode.

 

[WEDGE]

Rear diff is always in use. I think you maybe thinking of the transfer case. I don't know if the two are in the same unit on the Expedition and therefore share gear oil. Either way, the fluid in the rear diff is going to get used even in 2 wheel mode as the Expedition is rear wheel drive when in 2 wheel mode.

Rear diff and transfer case DO NOT share oil. Only thing they share is the rear driveshaft

 

[Trainmaster]

As others have said, millions of cars out there and probably 99% have never had the rear end oil changed. Virtually none of them fail. Spend your money elsewhere, unless you just want to be very safe.

 

[ExplorerTom]

Change it.

 

[07navi]

I ag

As others have said, millions of cars out there and probably 99% have never had the rear end oil changed. Virtually none of them fail. Spend your money elsewhere, unless you just want to be very safe.

I agree, it sounds like it's horrible to leave it in but it's synthetic and no contaminants like elsewhere. The only thing that kills them is water and leaks.

 

[WEDGE]

I recently changed the rear diff and transfer case oils in my 2010 and my sister's 2007 Expeditions. I don't believe that "lubed for life" B.S. Oils break down, they do not last forever. Ever seen the transfer case or "PTU" in a Ford Edge NOT blow up? They're sealed units from the factory and only hold a quart or so of oil. They burn up the oil all the time. So yes I would recommend changing the diff oils.

 

[Vancouver Bob]

It's settled... based on opinions, you should either change it or just leave it . You're choice.

I didn't change mine until I had the gears changed. That was at over 200K miles. Then changed it again some miles later as recommended because of the new gears (and lockers). If not for that I wouldn't have touched it. But that's just me.

 

[ExplorerTom]

Then changed it again some miles later as recommended because of the new gears (and lockers). If not for that I wouldn't have touched it. But that's just me.

So what’s the difference between factory installed gears on the assembly line vs new gears at 200k miles? Why change the oil after 500 miles on the gears installed at 200k miles but yet the factory installed gears are somehow “lubed for life”? Does the factory use special gears/bearings with special lube? Spoiler alert: they don’t.

 

[07navi]

It seems like you should change it but it

So what’s the difference between factory installed gears on the assembly line vs new gears at 200k miles? Why change the oil after 500 miles on the gears installed at 200k miles but yet the factory installed gears are somehow “lubed for life”? Does the factory use special gears/bearings with special lube? Spoiler alert: they don’t.

He changed it because somebody said it was recommended on the new ones (for no good reason) and it was apart so he changed it. Yes the factory does use special synthetic oil but gears are gears............very hard. I might add that I specialized in transmissions and rear ends when I was a mechanic.

 

[Vancouver Bob]

So what’s the difference between factory installed gears on the assembly line vs new gears at 200k miles? Why change the oil after 500 miles on the gears installed at 200k miles but yet the factory installed gears are somehow “lubed for life”? Does the factory use special gears/bearings with special lube? Spoiler alert: they don’t.

You mean the difference between factory gears installed at the factory vs third party gears installed by a fourth party? I can think of a short list of things. That said, Nitro gear has specific break in instructions for their gears. For seemingly good reasons and that's why I changed the oil. For comparison, there were no gear break-in instructions when I bought the Expedition .