Rear FX4 Differential Fluid

[mavhopefull]

Hi all,

I'm ready to replace the Front PTU and Rear Differential Fluids on my FX4 Maverick. In reading through some posts I'm finding some conflicting information. So, I called the dealer and these are the correct part numbers. Let me know if you've seen this before.

Front PTU
XY-75W85-QL

• Motorcraft® SAE 75W-85 Premium Synthetic Hypoid Gear Lubricant is an excellent multi-purpose extreme pressure lubricant recommended by Ford Motor Company as meeting warranty requirements. It is recommended for conventional and limited-slip differentials of vehicles that specify a fluid meeting WSS-M2C942-A

Rear Differential
XY-75W-QL - Disconnect Rear Drive Unit Fluid

• Motorcraft® SAE 75W Disconnect Rear Drive Unit Fluid is specifically formulated for Ford disconnect rear drive units with a low offset hypoid gear
• Developed with a lower viscosity to improve axle efficiency and fuel economy
• Motorcraft® SAE 75W Disconnect Rear Drive Unit Fluid is formulated with synthetic base stocks, friction modifiers, antiwear, and extreme pressure additives to provide gear protection and smooth clutch operation
• Use only in Ford Disconnect Rear Drive Units
• Do not use conventional high-offset hypoid gear axles where SAE 75W-85, 75W-90, 80W-90, or 75W-140 is recommended.

10/28/2023 Update
My First YouTube Video - Rear Disconnect Unit/Differential Fluid Change
Hi Folks. I finally got around to start the fluid changes on my Maverick. Here's my first-ever YouTube Video. I hope to have more in the coming days.



10/31/2023 Update
My Second YouTube Video - Front PTU Fluid Change
This is my second video. I hope you find it helpful. The third episode will be on changing the transmission fluid.

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[dalola]

Too lazy to check, how does that compare to the owners manual?

 

[jcnnjc]

How many miles do you have on your Maverick?
I have thought about when to change all the drivetrain fluids.
Im only at 12k now so, hopefully a little ways off.

thanks for the info

 

[mavhopefull]

Too lazy to check, how does that compare to the owners manual?

If you find it in the manual let us all know.

 

[mavhopefull]

How many miles do you have on your Maverick?
I have thought about when to change all the drivetrain fluids.
Im only at 12k now so, hopefully a little ways off.

thanks for the info

I'm going to do the initial fluid change at 10k to check the condition. I've been doing a lot of towing. Then at the regular 30k intervals.

 

[dalola]

If you find it in the manual let us all know.

Sure enough....that's pretty dumb on Ford's part....just don't include a maintenance item spec.

Do you have the capacities for each?

 

[mavhopefull]

Sure enough....that's pretty dumb on Ford's part....just don't include a maintenance item spec.

Do you have the capacities for each?

When I do the work, I will measure what I get out. The dealer said two pints for the rear but he wasn't sure.

 

[LC48]

When I do the work, I will measure what I get out. The dealer said two pints for the rear but he wasn't sure.

Service manual specs are 1.6 pints for the RDU, @2mm below bottom of filler hole.......so early service is a good idea

 

[Montana]

Thanks for sharing! Getting this done ASAP. I'm at just under 12k.

I saw a post where someone used Amsoil 75w-140 for the PTU. Here:

https://www.mavericktruckclub.com/f...-ptu-fluid-service-done-results-photos.19246/

Not too sure about that. Seems like everyone else is saying 75w-85 and using the MC stuff... But damn it's pricey. I'd much rather go Amsoil for that price. They have a 75w-90. Thoughts?

Quick search showed me .5qt for the PTU and 1.4qt for the rear dif?

 

[dalola]

Thanks for sharing! Getting this done ASAP. I'm at just under 12k.

I saw a post where someone used Amsoil 75w-140 for the PTU. Here:

https://www.mavericktruckclub.com/f...-ptu-fluid-service-done-results-photos.19246/

Not too sure about that. Seems like everyone else is saying 75w-85 and using the MC stuff... But damn it's pricey. I'd much rather go Amsoil for that price. They have a 75w-90. Thoughts?

Quick search showed me .5qt for the PTU and 1.4qt for the rear dif?

Don't even bother trying to get these fluids from a Ford dealer... for whatever reason, their prices on them are ridiculous. I found Rock Auto to have the best price for the Motorcraft fluids, ~$30/qt. & reasonable shipping. You'll need one of each for a D&R.

 

[Bob The Builder]

Good info here. Gonna put this thread on my watch list. Thank you.

 

[Bob The Builder]

Question for the knowledgeable here. I will be driving my Maverick 3-4K miles a year. I change my oil based on the calendar, every 6 months, as opposed to mileage. I would assume the same should apply to the differentials. What would be conventional wisdom on how ofter to service these differentials based on the calendar and not mileage. I'm thinking waiting 8-10 years to hit 30 K miles is not the right option.

 

[dalola]

Question for the knowledgeable here. I will be driving my Maverick 3-4K miles a year. I change my oil based on the calendar, every 6 months, as opposed to mileage. I would assume the same should apply to the differentials. What would be conventional wisdom on how ofter to service these differentials based on the calendar and not mileage. I'm thinking waiting 8-10 years to hit 30 K miles is not the right option.

In your use case, I would change engine oil, trans fluid, PTU, & Diff after one year, then engine oil annually, other fluids (including brakes & coolant) every 3-4 years. That is, if you plan to keep your Mav for eternity. If it's a short term purchase, follow the OLM/maintenance schedule.

 

[Montana]

Question for the knowledgeable here. I will be driving my Maverick 3-4K miles a year. I change my oil based on the calendar, every 6 months, as opposed to mileage. I would assume the same should apply to the differentials. What would be conventional wisdom on how ofter to service these differentials based on the calendar and not mileage. I'm thinking waiting 8-10 years to hit 30 K miles is not the right option.

Yea I agree with the poster above. At minimum, once every two years. Condensation is the killer is your situation.

Don't even bother trying to get these fluids from a Ford dealer... for whatever reason, their prices on them are ridiculous. I found Rock Auto to have the best price for the Motorcraft fluids, ~$30/qt. & reasonable shipping. You'll need one of each for a D&R.

That's what I was afraid of and why I was considering Amsoil or Redline.
Amsoil has a 75w-90 but they add friction modifiers (not sure if that is applicable in this situation or not). The other poster I quoted using 75w-140 doesn't seem to be correct. XY-75W85-QL does specify for limited slip applications you need to add XL-3 (friction modifier). I just can't find any info stating if the PTU or rear dif needs it.

I'll wait for some more input before I continue with this project, but I am going into town today and I'll check the prices. I would much rather just buy the Amsoil. There is definitely some conflicting information on the correct weight.

 

[Bob The Builder]

In your use case, I would change engine oil, trans fluid, PTU, & Diff after one year, then engine oil annually, other fluids (including brakes & coolant) every 3-4 years. That is, if you plan to keep your Mav for eternity. If it's a short term purchase, follow the OLM/maintenance schedule.

I am 74 and planning on keeping my Maverick as my last truck. Hopefully that is closer to eternity than it is short term. Hahahahaha.

Thanx.

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