Transfer case, front axle, and rear diff fluid change.

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keny01998

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My 2019 Expedition 4WD has around 21k miles and I'm thinking about change out the fluid for transfer case, front axle, and rear diff fluid. I know Ford does not call for these services until like 100k miles but I like to keep my Exp in good shape since I tow 4000 lbs boat in summer time. I have a few questions.

Has anyone change these fluids on the new Expedition?

Does rear differential have drain plug like older Expedition or I have to crack the case like F150? I'm going to use Valvoline synthetic 75-90 for both rear and front axle.

Do you recommend to use anything else except Mercon LV for transfer case?

Thanks,
 

Soliyou

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The rear diff and transfer case are very easy to service since they have a drain plug. I did both last year. Bought a small hand operated fluid pump. For the front diff, it is probably easier to suck the old fluid out from the fill plug since the cover is very close to the steering rack.

My transfer case (with 4A) has a big warning saying “use Mercon LV only”

for the rear axle, since mine has eLSD, I decided to stick with the recommended Ford 75-85 plus the friction modifier.

Two more things, Ford recommends changing the drain plug every time you change the fluid. You can reuse the old one if you apply thread oil sealant https://www.permatex.com/products/t...high-performance-thread-sealant/?locale=en_us. You can crack these cases easily if you over torque the plugs, so be careful with that.
 
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Plati

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Well you asked for opinions and I think that is absurd! Exclamation point. On my 2014, not due until 150k. Not sure what your year advises in Owners Manual. I think it's about as useful as changing the air in your tires.

I just changed front rear & transfer case on my 2014 at 108k just so I'm good for another 7 years and my mechanic said it was not necessary but did them anyway.

You will get every opinion under the sun from this Forum.
 

byathread

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Well you asked for opinions and I think that is absurd! Exclamation point. On my 2014, not due until 150k. Not sure what your year advises in Owners Manual. I think it's about as useful as changing the air in your tires.

I just changed front rear & transfer case on my 2014 at 108k just so I'm good for another 7 years and my mechanic said it was not necessary but did them anyway.

You will get every opinion under the sun from this Forum.
Yup, I'm also in the "useless as **** on a bull changing those fluids at 21K" camp...

That being said, I am also a huge fan of doing what I want, so, I'd say if that is what you want to do go for it, man! [emoji41]
 

Gumby

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I did a transmission service and transfer case service at about 99800 kms (about 61,000 miles) at the dealer. The tranny service was about 2 hrs and cost with parts and labor $502.64. The transfer case was about 0.5 hrs and cost about $71.00. I have also had the rear pinion seal done 3 times (yes that is 3 friggin times) all under warranty. So that fluid must be clean AF.
 
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scottdm

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The only reason that I would consider changing diff fluids early would be if I had to drive through water deep enough that it may have gotten into the diff breathers.
 

Soliyou

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For my case, I was troubleshooting gear whine above 75 mph. So I decided to check the fluid condition and replaced them anyways.

That said, I am very glad that I did them. The rear end fluid specially was full of break in metals that shouldn’t be left circulating around clutch plates and eLSD pins.

The transfer case fluid was pretty dark but I guess it is a characteristic of Mercon LV.

In any case, I would not put more than 30k miles on these fluids based on my use.
 
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keny01998

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I just did the rear differential fluid today and it was easy process. I had to run to the store to buy the torch since those plugs would not budge and I didn't want to damage them. Over 2 quarts came out and the fluid was muddy black.

There were a lot of metal particles on the magnets. I cleaned the plugs up and reused them with red thread locker. I pumped in around 2.5 quart until the fluid drained out and trickled from the fill plug. Torqued the plugs around 18 ft/lb and called it done.

I couldn't do the transfer case or the front axle because I do not have the Mercon LV on hand and I have about 1.5 quart of Valvoline 75-90 left. I think front axle uses around 1.9 quart. I may wait until 30k miles to tackle them.

Thanks for your help especially Soliyou with the torch idea :)
 
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Soliyou

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I just did the rear differential fluid today and it was easy process. I had to run to the store to buy the torch since those plugs would not budge and I didn't want to damage them. Over 2 quarts came out and the fluid was muddy black.

There were a lot of metal particles on the magnets. I cleaned the plugs up and reused them with red thread locker. I pumped in around 2.5 quart until the fluid drained out and trickled from the fill plug. Torqued the plugs around 18 ft/lb and called it done.

I couldn't do the transfer case or the front axle because I do not have the Mercon LV on hand and I have about 1.5 quart of Valvoline 75-90 left. I think front axle uses around 1.9 quart. I may wait until 30k miles to tackle them.

Thanks for your help especially Soliyou with the torch idea :)

Glad it went well. I don’t think red thread locker is the correct product! Removing it will be a big fight. The correct product is oil thread sealant. It is like a white gooey paste that replaces Teflon tape
 

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