Speed sensor/trans issue

[Njgcoupe05]

Hi guys i am new to this site so I hope this thread is in the correct place, I have a 98 ranger, 3.0 automatic. My speedo started jumping around so I replaced the sensor that is located in the rear, and in 2 weeks it started doing it again, so I then bought a sensor directly from ford and it didn't go away now it's causing my trans to down shift and up shift when the speedo is bouncing all over, I changed the gear fluid, can anyone help me diagnos the problem?Thanks for your time and help

 

[Njgcoupe05]

And also the od light flashes after a little bit of driving, could my PSOM be bad causing this?

 

[Earl43P]

The VSS has two wires, LG/BK and RD/PK. They go to the RABS Module (2wd) pins 3 and 10.

4WABS VSS also has LG/BK and RD/PK wires. They go to the 4WABS Module pins 22 and 21.

Look under the truck cab on the driver side and you'll find a large square electrical connector feeding through the floor, directly beneath the driver seat. That connector is prone to water intrusion and corrosion. Disconnect it, clean up the contacts and pack it with dielectric grease and reconnect it.

If that doesn't fix it, you may have a physical problem with the tone ring inside the axle.

Your transmission shifting problem is absolutely caused by the erratic VSS signal.

 

[Njgcoupe05]

I really hope that's the problem. I bout the truck from a guy that lived by the shore so I can definitely see that happening, thanks a lot for your input/help