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RDU Motor Actuator, failure advice? Part number?


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Hello, looked for help, but couldn't find it here, auto parts stores, or Google.

 

We are experiencing a very intermittent problem with our 2020 Edge Titanium 2.0L turbo, 84,000 mi.  So intermittent I cleared the DTC's out of the OBD, and cannot report them here.  Ugh, sorry...

 

The codes were about the RDU, that its motor actuator was reporting in one position, but it was functioning as if it were in another. 

 

My first stab at fixing was going to be to drain the RDU fluid, replace it with the special Motorcraft RDU Disconnect Fluid (XY-75W-QL).  I'll do that this weekend and check cabling, the vent, and anything else visual.

 

I'm suspecting I may need to swap-out the speed/position sensor and the actuator motor tho.  The blue guys here:

image.png.4e0ccd7c640b7b3296bfb0b21b350979.png

The local dealer tells me they're not sold separately, which feel like a load of BS. 

 

Any suggestions?  Even those two part numbers or a vendor?

 

Thank you,

-Jeff

 

 

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Welcome to the Forum, @Gnerffed!

 

The 2020 Edge Workshop Manual prescribes a specific Drive Cycle for diagnosis of Four-Wheel Drive concerns and it seemingly cautions against performing Pinpoint Testing unless the Drive Cycle elicits the Diagnostic Trouble Code (DTC)...

 

Four-Wheel Drive Systems

Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
 

Inspection and Verification

NOTE: For most AWD System DTCs to set, the AWD module must detect the fault on 2 consecutive trips.

    • 1) Record and clear DTCs from the AWD module.
    • 2) Accelerate the vehicle from 0-45 mph with light (10%) APP.
    • 3) Maintain 45 mph for 10 seconds.
    • 4) Gently slow to a stop.
    • 5) Repeat steps 2-4.
    • 6) Accelerate the vehicle from 0-45 mph with moderate (30%) APP.
    • 7) Maintain 45 mph for 10 seconds.
    • 😎 Gently slow to a stop.
    • 9) Repeat steps 6-8.
    • 10) Turn off ignition, wait 1 minute.
    • 11) Repeat steps 2-9 or until an AWD fault message is displayed in the IPC . Whichever is sooner.
    • 12) Retrieve continuous memory DTCs from the AWD module. If no DTCs are present, the concern may be intermittent. Do not perform a pinpoint test unless the concern is present.
  •  

 

Attached below are all Wiring and Workshop Manual sections related to Rear Drive Unit (RDU), including diagnostic Pinpoint Tests, and removal and installation procedures for the RDU Actuator Motor, RDU Speed Sensor, and All Wheel Drive (AWD) Module.

 

If you progress through diagnostic Pinpoint Test(s) and identify a faulty component, then I'll try to determine an appropriate part number.

 

Additional documents will be attached to an immediately following post, due to Forum file attachment limitations.

 

Good luck!

 

Rear Drive Axle and Differential - System Operation and Component Description - 2020 Edge Workshop Manual.pdf

Four-Wheel Drive Systems - System Operation and Component Description - 2020 Edge Workshop Manual.pdf

Four-Wheel Drive Systems - Diagnosis and Testing - EDITED - Diagnostic Drive Cycle - 2020 Edge Workshop Manual.pdf

Four-Wheel Drive Systems - Diagnosis and Testing - EDITED - RDU-only PPTs - 2020 Edge Workshop Manual.pdf

RDU Actuator Motor & Speed Sensor to AWD Module - Wiring Diagram - 2020 Edge.pdf

RDU Actuator Motor & Speed Sensor to AWD Module - Inline Connector C4001 Details - 2020 Edge.pdf

Inline Connector C4001 Location - UNDER VEHICLE - 2020 Edge.pdf

Rear Drive Unit (RDU) Actuator Motor - Connector C3396A Details - 2020 Edge.pdf

Rear Drive Unit (RDU) Actuator Motor - Connector C3396A Location - 2020 Edge.pdf

Rear Drive Unit (RDU) Speed Sensor - Connector C3396B Details - 2020 Edge.pdf

Rear Drive Unit (RDU) Speed Sensor - Connector C3396B Location - 2020 Edge.pdf

ALL WHEEL DRIVE (AWD) MODULE - Connector C3841 Details - 2020 Edge.pdf

Rear Drive Unit (RDU) Actuator Motor - Removal and Installation - 2020 Edge Workshop Manual.pdf

Rear Drive Unit (RDU) Speed Sensor - Removal and Installation - 2020 Edge Workshop Manual.pdf

All-Wheel Drive (AWD) Module - Removal and Installation - 2020 Edge Workshop Manual.pdf

 

Edited by Haz
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  • 3 weeks later...

Update, finally.

 

Sorry, guys, I've been distracted a few times and have sorted-out the RDU fluid on Sunday, wrt my actuator position error.

 

So, I cleared the DTC's, jacked the Edge (all four, 'had a BSR issue I wanted to resolve as well, jacked the RDU back to it's standard ride height relative to other components), drained & flushed the fluid per the manual excerpts Haz furnished (fluid was opaque, black, & thin), replaced it with Motorcraft Rear Disconnect Fluid (p/n: XY-75W-QL), and went through the verification steps.  Additionally, we have about 200 further miles on the car (some in slippery/muddy conditions).

 

No more warnings about the RDU or that actuator motor!

 

Go figger, maintenance matters.  btw, I'm not seeing this, or the PTU fluid changes listed in the owners manual...

 

I've serviced the transaxle as well, PTU is up next (looks like access is an issue, but, it'll get done).  Seals look ok along the driveline...

 

Thank you all!

 

-Jeff B.

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I don't understand why the PTU and RDU aren't listed as routine service items in the owner's manual. How can any car manufacturer expect any fluid to last the life of the vehicle. Seem like all the PTU failures I've heard about are because of fluid that has never been changed. 

Also heard stories about Ford Dealerships that didn't even know about the PTU or RDU service!

Thanks for the update! Looks like I might have to do those fluid changes myself one day, I don't know if My Ford Dealership is capable.🙃

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9 hours ago, STBEAST said:

I don't understand why the PTU and RDU aren't listed as routine service items in the owner's manual.

 

Seem like all the PTU failures I've heard about are because of fluid that has never been changed. 

You answered your own question..

Not trying to ruffle anyone's feathers but the pattern is kind of obvious at some point.

Same reason GM canceled the 3800.

It lasted too long.

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STBEAST & Cerberus,

 

Yeah, I know, the RDU fluid that came out was devoid of any real viscosity, I've got to say--WD40 thickness, water, 1-centistoke!

 

No wonder the RDU actuator couldn't engage, or disconnect the AWD, eh?  We'll see about the PTU soon, but I'd be surprised if it's any different (though a different fluid is specified). 

 

By the way, ask about how easy it was to get to the fill cap out with a cross-member in line with it (and it gets tighter as the plug backs-out, see attached image)...

 

This, by the way, is a car with mostly "Detroit metro to Marquette, MI" miles on it.  Highway, easy. I'm not trying to sell the car, I mean it, lol...

 

-Jeff

rdu_fill.jpg

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