Rear Diff Oil

[ANGEL TORES]

Hello, I am getting ready to change the oil in my rear differential. So far I see no videos on youtube on that procedure. I'm sure I'll be able to figure something out as far as that. Does anyone have any Ideas on what gear oil weight I should go with? I own a 2015 Expi and I tow a 7500 lbs camper. I want to get her ready for a long trip to Florida from NJ in March so I am taking time now to get everything right for when I do my maintenance for the trip. Looking forward to hearing some good suggestions on what weight I should go with.

 

[Black]

It is very simple.
Unscrew the fill plug first and then unscrew the drain plug.
I highly suggest putting a torch on the plugs. Ford uses red loctite and I buggered mine up and had to buy new ones.
Put your drain plug back in, pump new oil in, then put the fill plug back in.
And you are done.
https://www.expeditionforum.com/posts/323500/

Amsoil 75w-90 Severe Gear Oil (Black bottle not the silver) is what you want to use.
If you have a LSD you’ll want to add friction modifier. I use the Motorcraft stuff from the dealer. Amsoil has their version called SlipLoc I believe but I have never seen it stocked locally where I purchase my Amsoil but the dealer always has the Motorcraft.

May as well do the transfer case and front diff if you are 4wd while you are under there.
Transfer case is cake and the plugs come out super easy since it is an aluminum housing.
The front diff is a bit more of a pain and the fluid needs to be suctioned out.

Video if you need.

 

[Franklin Jones]

Not to hijack or resurrect an old thread, but...

I was checking my owners manual for the proper fluids for diff changes, and noticed the front diff calls for 80w/90, but the rear calls for 75w/140.

Anyone know the reason for the difference? Does it really matter?

 

[Plati]

Not to hijack or resurrect an old thread, but...

I was checking my owners manual for the proper fluids for diff changes, and noticed the front diff calls for 80w/90, but the rear calls for 75w/140.

Anyone know the reason for the difference? Does it really matter?

What do you mean ...?

Does it matter which lubricant you use OR does it matter why they are spec'd different?

It?

 

[Franklin Jones]

What do you mean ...?

Does it matter which lubricant you use OR does it matter why they are spec'd different?

It?

well if you can understand the mind of a ford engineer and can answer the second, then great! ;D

But really I was wondering if it mattered which fluid I used; whether I could use the same in each, or if it could cause an expensive oops?

 

[TobyU]

well if you can understand the mind of a ford engineer and can answer the second, then great! ;D

But really I was wondering if it mattered which fluid I used; whether I could use the same in each, or if it could cause an expensive oops?

If you wanted to do that 75w-140 in both would be the best.
In reality ANY gear lube would suffice just fine, as long as limited slip ones get a limited slip additive.
If you use a gear lube in one and it is full and it has problem or failure IT WON'T be because of the weight of the gear lube.
It just won't.

Tons of car have 80w-90 in the rear. Large trucks even....and they go 300K or more miles.
The rear diff in one of the most durable items on car. Less when you get into aluminum irs with half shafts etc