2020 PTU and Rear Diff Fluid?

[SteveO2019]

Greetngs all, I have a 2019 ST, app 70,000 miles. This is my 3rd Edge, first 2 were Titaniums and both were totaled by idiot drivers. This one is by far the favorite, started making a odd knocking sound in rifght rear only when taking off and in right turn, does not do it id left turn. Anyone else experience this? Guess it will go to shop next week.

[Samurai Edge]

Sounds like something loose in the suspension.  Could have a loose / failed rear shock, which would make it simple to fix.

 

Have you looked around the area to see if you can see anything out of place; ie: loose inner fender well, shock not properly bolted in place, etc.

You can only see so much with the wheel / tire installed.

[enigma-2]

This is a highly documented pattern failure on 2019+ Ford AWD. It's probably a failing Active Torque Coupling Unit on the Rear Differential.

 

Starting with the 2919 edges, Ford changed the AWD disconnect system that frequently suffers from internal clutch pack chatter or mechanical failure.

 

When you take off or turn right  the vehicle weight transfers  and forces the rear differential to send torque to the left rear wheel while slipping the inner right wheel, which triggers a distinct clunking, knocking, or thumping sound from that rear area.

 

No recalls on the coupler, but a recall on the rdu. 

21S02 (Rear Drive Unit Lubricant Level.) Applies to certain Edges regarding a low lubricant fill level in the rear drive unit. If the fluid was below the minimum level, the axle was supposed to be replaced free of charge. You should check if your specific VIN was ever flagged for this, as running low on fluid from the factory causes the exact premature failure and clunking you are experiencing.

 

There's TSB 21-2389 for Rear Actuator Noise.

 

Check for recalls by getting your VIN and go to the NHTSA Recall Lookup Tool.

https://share.google/NTvPbYbGnMtqpp5ND

 

(Good reason to have an extended warranty.)

 

 

[garycrist]

I've wondered about running 75-140 with some friction modifiers. (like in a 8.8 LSD)

It should quiet down the chatter some by making the fluid slippier.

 

In looking at the failures so far. One thing is the bearing failures due to overworked thin fluids.

Then as you stated above clutch failure. All of this for fuel economy?

[Samurai Edge]

In which vehicle?  The 2022 is not designed to use that weight gear oil

[enigma-2]

Found this on YouTube. 

 

[Samurai Edge]

That's an excellent video.  And the whole process only takes 16 minutes!  😃

[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

[bruker]

I have a 2020 Edge and it's starting to make the rumbling sound when making a slow right turn. I crawled under and noticed the front of the rear diff is a little damp with oil. Is that also indicative that the Active Torque Coupling Unit is starting to fail? The video above is for I think he said a 2013 is the process the same for the 2020? Thanks for any help.  

[Samurai Edge]

Did you have the software update that resolves issues with the rear diff making rumble noises?   I had some of that on left & right turns, randomly, and that solved that issue.

 

Can you see where the leak is coming from?

  - Is it from the connection to the rear diff?

  - Is it coming from on top of the rear diff?  There is typically a breather hole on top of the rear diff to allow for expansion of air in the rear diff as the oil heats up and expands.  Remember the rear diff is not completely full.

  - Did you drive through something that makes it look like the rear diff is leaking?

 

The above procedure does work on a 2020 but I suggest you make sure where the leak is actually coming from before you tear into this project.

[bruker]

Here's a pic I just took from the driver's side. The area circled is where there's a light coating of fluid. 

 

[Samurai Edge]

Honestly, that could be almost anything.  Car undersides pick up all kinds of dirt & grease from the roadway all the time.

 

Do you park the car in the same place, the same way everytime?

Are there any wet spots on the pavement directly under where the RDU sits?

What happens when you place your finger on that area shown in the picture?

 

All I'm saying is don't jump to conclusions just because you watched that video.

[garycrist]

Are you sure it is not from the drain plug? Clean it off with some Brakleen and monitor.

[bruker]

Yep, park in the same place every night. No spots or drips on the floor. When I wipe it with my finger it's wet but doesn't really have much of a smell. The drain and fill plugs are tight and no evidence of leaking.  

[Samurai Edge]

It wouldn't be from the drain plug since that's in a different area of the RDU.

 

If you are not seeing any spots on the floor, I wouldn't be too concerned right now.  I would just keep an eye out for any leaks in the future.

 

Get that software upgrade done and see if that makes the problem go away.

[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

[bruker]

I'm not the original owner and there are no open recalls for my Edge. Does that mean the software update's probably been done already?  

[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

 

[Samurai Edge]

The software update is not a recall.  It is a TSB ( Technical Service Bulletin ).  You do not get notices on TSBs.  The dealership does not normally check for TSBs unless, maybe, a symptom you have coincides with the issue / symptom you are currently having.  My dealership at the time fought with me and refused to perform the TSBs.

 

In other words, you are basically on your own to check for TSBs, determine if you are affected by any one or more TSBs, and then get them resolved.

 

Software updates are easy.  You can do them from your display.  You do not have to leave your car turned on.  As long as you have Wi-Fi available, once initiated the update will run on its own.  Allegedly these software updates are supposed to update themselves automatically, but apparently they don't.

 

I found a number of recurring TSBs that needed to be attended to.  There were two (2) that kept repeating themselves over and  over, with different TSB numbers.  Go Figure.

 

Those two (2) TSBs were   1.  A Display Update   and    2.  An update to resolve the RDU clunking.   

Once installed, they worked perfectly.

 

The updates actually took over 8 hours to complete while the car sat overnight.

Edited August 22 by Samurai Edge

[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. 

[bruker]

I had no idea you could do the updates from the display. I just went and checked, and it said the updates are current as of today's date 8-22-26. When I touch the Scan for Updates button I get the spinning circles. How long should I have to wait to see what updates might come up? It is connected to WIFI.

[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.

[Samurai Edge]

I had no idea either.  I thought it had to be done by the dealership.  

 

I did this a year ago but, IIRC, I tried it a couple of times because it looked like it was doing nothing, just spinning its wheel.  Eventually I just let it ride for a while before it started working.  Remember that how long it takes is partially determined by your WiFi connection and network traffic.

 

I believe I finally did an internet search to find the correct way to do the update install and that is how I got it to work.