E40D Problems or PSOM?

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Apr 25, 2026 | 01:13 PM

#16

Bulletz4Breakfast

4th Gear

Joined: Apr 2026

Posts: 4

Likes: 0

Quote:

Originally Posted by rla2005

No. Electrically the RABS control module may be loading down the VSS signal. Removing the fuse is not a substitute. You have to remove the connector to the RABS module located behind the glovebox.

Hey I have 1994 Ford F150 5.0L E4OD transmission with 4WD and same symptoms harsh shifting with clunk, changed from OEM sensor that read OL on resistance to a Dorman VSS Sensor on diff, it made shifting very smooth for a while then had the clunk and extended late shifting.
The dorman added the speedometer needle wiggle at around 50-65mph.
I did find some small metal shavings on old sensor magnet tip and fluid is brown black like old motor oil. I'm thinking I need to change gear oil next month.

I need to know if the correct Motorcraft VSS Sensor is DY-1123 or p/n F85Z-9E731-AB

Or if that's the wrong part number, I want the OEM sensor so no air gap or different magnet and every chance for a clean signal.

How do I test the PSOM signal from VSS and PSOM to wherever it goes RABS/PCM?
Also if I unplug that black connector and drive and it does fine, that means the RABS is bad and if it's in the circuit how does the VSS get signal to PCM with it unplugged? I'm not familiar with this circuit at all...Can the RABS/4WABS be bypassed and left out I can't spend $1000

Last edited by Bulletz4Breakfast; Apr 25, 2026 at 01:15 PM.

May 25, 2026 | 05:37 PM

#17

wannabuyaford

Thread Starter

Tuned

Joined: Jun 2023

Posts: 318

Likes: 25

Quote:

Originally Posted by Bulletz4Breakfast

I don't know the Motorcraft part #. I used an expensive NAPA VSS.

When I remove the RABS module (behind the glove box, easy removal) the speedo stops wiggling so much, but using two different JY models brings the wiggle back. Yes I've driven without the module, but I don't have ABS in that case.

I'm still thinking the PSOM might need to be replaced.

Also, see if your trans fluid is too high. I had good luck re: clunking recently after having low trans fluid (toward the bottom of the hash mark.) But the speedo is still wild.