Phil Larsen

I was reading through my owners manual to determine when and which fluids to use change my rear differential fluid.

Here is what I found:

It says, "5.5 pints (2.6L) Motorcraft SAE 75W-140 Rear Synthetic Axle Lubricant". And then there is a small footnote with a 4 after "2.6L" and then another small footnote with a 5 after "Lubricant".

So I flip the page and here is what the 5 footnote says:

"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 beed submerged in water. The axle lubricant should be changed any time the rear axle has been submerged in water."

So I don't have to change rear differential fluid...EVER? Crazy.

Maybe I just do it every 100,000 miles.

ReaperHWK

I have a 2006 F150 with about 145k miles on it, NEVER changed the diff fluid and you don't need too per the maintenance schedule.


No issues with my diff.


I MIGHT change it at 200k.........

roachslayer

I'm not sure I trust this. I'm at 185k and I popped the filler plug to see the fluid... it's pretty dang dark.

Trust the people that make money off you when things break, that you don't need to add fluid ever? Yeah, I just dunno about this.

...bearing in mind also, after 36k and 5 years, Ford doesn't care about your vehicle. Yeah...

Eric Kleven

You can never go wrong by changing it. Who's definition of 'lifetime' is being used here? Yours may be significantly different than the people who wrote the manual.

650NutKase

This is the way I see all these "lifetime" fills. Unless the manufacturer gives me a lifetime warranty on that part, I'm going to change the fluid...Same issue with the gf's Toyota. They claim a lifetime trans fluid. Yeah, I'm changing that soon too lol. I like to keep my cars more than 2 years

ReaperHWK

I think lifetime for Ford is 150k miles, the service schedule stops after that.

roachslayer

I just finished changing mine today. Seriously folks... Lifetime is not some magical infinity thing. This is dirty oil at 185k, some light hauling, mostly regular driving.


This pic shows dirty 75W-140 from the rear diff, 16 years of wear. On the right is clean motor oil. Below is nasty smudge from the bottom of the case. And believe me, it looks way worse when not thinned out on this white paper! This stuff is way past due.

Replaced with Royal Purple 75W-140 synthetic with additive built in. Now I'm certain its good for the remaining "lifetime" of the vehicle.

I used Ultra Blue gasket maker pretty sparingly but thorough, but it would have been nice to use a formed gasket. Some oozed out on the outside edge, and I imagine inside as well. Oh well, it came from ford like that too, lots of silicone ooze inside.

PerryB

Yes, lubricated for the life of the axle........

650NutKase

So does Ford give warranty coverage in case an axle dies due to lack of maintenance before 150k? Not being sarcastic...This is the main reason I change fluids when they are dirty. Saves me the headache

Eric Kleven

Think of 'lifetime' this way:

If you build a man a fire, you keep him warm for a while.
If you set a man on fire, you keep him warm for the rest of his life.