Rear Diff Fluid?

[bruker]

What's the correct rear diff fluid for a 2020 Edge and where did you get it from? Thanks

[1004ron]

Looks like the owner's manual calls for:

 

Rear Axle

Variant	Quantity
All.	28.1 ± 1.0 fl oz (830 ± 30 ml)

 

Materials

Name	Specification
Motorcraft® Disconnect Rear Drive Unit Fluid XY-75W-QL	-

 

MOTORCRAFT XY75WQL Gear Oil | Shop Now at RockAuto

[Samurai Edge]

The Owner's Manual?  That's a funny place to look.   😉

 

That particular option is ridiculously / outrageously expensive.  This is what I use :  Redline MT-LV 70W/75W  ( Full Synthetic )

 

[omar302]

2 hours ago, Samurai Edge said:

The Owner's Manual?  That's a funny place to look.   😉

 

That particular option is ridiculously / outrageously expensive.  This is what I use :  Redline MT-LV 70W/75W  ( Full Synthetic )

 

 

The Motorcraft oil is specifically made(formulated) for the Ford "Disconnect Rear Drive Unit". Hence assume it is not a general gear oil like other makes. The Motorcraft specs (link) states:

 

• 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 in conventional high-offset hypoid gear axles where SAE 75W-85, 75W-90, 80W-90 or 75W-140 is recommended

[Samurai Edge]

59 minutes ago, omar302 said:

 

The Motorcraft oil is specifically made(formulated) for the Ford "Disconnect Rear Drive Unit". Hence assume it is not a general gear oil like other makes. The Motorcraft specs (link) states:

 

• 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 in conventional high-offset hypoid gear axles where SAE 75W-85, 75W-90, 80W-90 or 75W-140 is recommended

 

Good repeat of the manufacturer's position.  It really means nothing.

As long as someone uses an oil, gear oil, etc., that, at a minimum, meets the standards of the specified oil, gear oil, etc., then said oil performs the same, at a minimum, of the specified oil.

 

Redline MT-LV 70W/75W  ( Full Synthetic ) meets that specification.

https://www.redlineoil.com/mt-lv-70w75w

 

[omar302]

22 minutes ago, Samurai Edge said:

 

Good repeat of the manufacturer's position.  It really means nothing.

As long as someone uses an oil, gear oil, etc., that, at a minimum, meets the standards of the specified oil, gear oil, etc., then said oil performs the same, at a minimum, of the specified oil.

 

Redline MT-LV 70W/75W  ( Full Synthetic ) meets that specification.

https://www.redlineoil.com/mt-lv-70w75w

 

 

Generally I would agree with you, but I have not seen Ford develope a "specific" oil for no reason. Usually their oils have some spec and the manual would state you should use an oil that meets their minimum spec, for the "disconnect" PTU and RDU used on 2019+ Edges, I don't recall reading the same. 

 

In the link for for redline MT-LV specs you posted, it is clearly stated:

• MT-LV, MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears

Additionally, the OEM compatibility does not include Ford's disconnect oil. 

[Samurai Edge]

 

 

9 minutes ago, omar302 said:

 

Generally I would agree with you, but I have not seen Ford develope a "specific" oil for no reason. 

 

I don't disagree with you but that doesn't mean they are the only game in town.  I do use Motorcraft oils because  1.)  As you said above   and   2.) Many times they are equal or lower in price than a competitor, ie; Redline or Motul.  However, the RDU Disconnect fluid is stupidly overpriced so I went looking for an alternative.

 

When I called Redline's Tech Service line, they stated that their MT-LV 70W/75W  ( Full Synthetic ) meets that specification of the Motorcraft Disconnect Rear Drive Unit Fluid XY-75W-QL.

 

I don't just swap out one for another without researching alternatives.  As far as I could find, only Redline clearly stated that their MT-LV 70W/75W  ( Full Synthetic ) meets that specification of the Motorcraft Disconnect Rear Drive Unit Fluid XY-75W-QL.  No one else did.

 

I'll spend 1/2 the price on a known product line that I have been using for years.

[1004ron]

Generally the differential oils contain friction modifiers which cause issues with wet clutches. 

 

Similar reason why its not good to use car engine oil in a motorcycle due to the wet clutch - motorcycle engine oil does not contain friction modifiers.

 

Redline and Amsoil are top rated, so if they put it in writing that their oil is compatible I'd trust that.

The Redline website kind-of indicates that its compatible.

 

Interesting discussion here:

https://bobistheoilguy.com/forums/threads/rear-differential-rdu-fluid-amsoil-alternative.401168/

 

And here:

https://www.mavericktruckclub.com/forum/threads/rdu-rear-diff-non-oem-fluid-change-motocraft-xy-75w-qd-is-roughly-equivalent-to-a-synchromesh-gl-4-manual-transmission-fluid-not-a-gear-oil.75331/

[omar302]

1 hour ago, Samurai Edge said:

When I called Redline's Tech Service line, they stated that their MT-LV 70W/75W  ( Full Synthetic ) meets that specification of the Motorcraft Disconnect Rear Drive Unit Fluid XY-75W-QL.

 

1 hour ago, 1004ron said:

The Redline website kind-of indicates that its compatible.

 

Sorry, but I couldn't find on the Redline website where it states their oil MT-LV 70W/75W is compatible with the Motorcraft XY-75W-QL. It states it is compatible with Ford's XT-11-QDC (WSS-M2C200-D2) which is Ford's dual clutch fluid (link). 

 

Checking the recommended fluids based on car make/model does bring up the MT-LV 70W/75W as a recommendation for the rear differential, but if you enter a 2019 Edge it would bring up 75W90 GL-5 GEAR OIL, so their recommendation page is flawed. 

[Samurai Edge]

22 hours ago, omar302 said:

 

The Motorcraft oil is specifically made(formulated) for the Ford "Disconnect Rear Drive Unit". Hence assume it is not a general gear oil like other makes. The Motorcraft specs (link) states:

 

• 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 in conventional high-offset hypoid gear axles where SAE 75W-85, 75W-90, 80W-90 or 75W-140 is recommended

 

I think you are missing something here in this explanation.

 

You have to remember that we are talking about the RDU gear oil and NOT the Viscous Coupler oil.  These are two (2) different things, two (2) separate units that work independently of each other but, in unison, complete the transfer of power to the rear wheels.

 

Every manufacturer states only use their brand fluid ( you pick which type of fluid ) in their vehicles.  Ford is no different.  That does not mean you HAVE to and it does not mean that using an appropriate alternate fluid is bad for the vehicle nor will it void warranty.  You just have to meet the minimum spec of the original manufacturer specs but exceeding them is even better.  

 

Remember that the RDU itself is just gears and bearings.  There are no clutches involved.  The clutches are in the Viscous Coupler and you can not change that fluid as it is a sealed unit.

 

In my opinion, after doing my own searches for alternates, and speaking directly to a Redline Tech concerning the differences between what is stated by Ford Manufacturing and what Redline states on their website for the Redline MT-LV 70W/75W gear oil, I am convinced one is equally compatible with the other.

 

That's my opinion and Redline's opinion.  If in doubt about a product, I go directly to the source and don't rely simply what I read on a label or a website.

 

You don't have to take my advice.  You, and anyone else that does not agree, or has doubts, should just use whatever Ford recommends.

 

[omar302]

3 hours ago, Samurai Edge said:

Every manufacturer states only use their brand fluid ( you pick which type of fluid ) in their vehicles.  Ford is no different.  That does not mean you HAVE to and it does not mean that using an appropriate alternate fluid is bad for the vehicle nor will it void warranty.  You just have to meet the minimum spec of the original manufacturer specs but exceeding them is even better.

 

The owners manual for the Ford Edge states to use oils that that meets the defined specification and viscosity grade.

They do "recommend" Motorcraft, but does not state to only use Motorcraft. 

Link to the 2024 Edge manual.

 

3 hours ago, Samurai Edge said:

Remember that the RDU itself is just gears and bearings.  There are no clutches involved.  The clutches are in the Viscous Coupler and you can not change that fluid as it is a sealed unit.

 

Not all gears are engineered or made the same, hence the different oil types and viscosities. 

 

3 hours ago, Samurai Edge said:

You don't have to take my advice.  You, and anyone else that does not agree, or has doubts, should just use whatever Ford recommends.

 

Well said.