every time i drive my 97 f150 the OD light on the shifter starts blinking and stays blinking until the vehicle is shut off when ever anything close to highway speeds are reached, although it has come on occassionaly at lower speeds. everything appears to remain normal as far as shifting and such and you can still take it in and out of overdrive. took it too a transmission place and they said the code was speed sensor error. so i took the speed sensor out of the diff and replaced it. I also checked the wiring from the frame to the diff and it appears to be okay. although it does not seem to affect the driveability it is annoying to have that light blinking all the time. Any input would be greatly appreciated.

 

You replaced the speed sensor on the tranny, not the sensor on the differential, like you stated?? The light prob. has to be reset. Hopefully that was the cause.

 

no the sensor on the diff is the one i replaced. Is there one on the tranny also. The light resets itself everytime you shut the vehicle off, but return after driving for awhile.

 

I may be mistaken, but the sensor on the top of the differential is for ABS, I believe. The speed sensor is near the tail shaft of the transmission

 

I believe you're thinkin of a manual tranny, the speed sensors are on the rear axles.

 

i noticed that there is some kind of sensor on the tail shaft of the transfer case. what is this and could it be causing my problem.

 

Look according to the repair manual, the vehicle speed sensor for the tranny, speedo and engine, is on the tail housing of the the tranny, near where the drive shaft is. The sensor on the rear differential ,on top, is for ABS. Is that the one you changed?? The new speed sensor should match up with the style you have, by that you should be able to tell where it is.

 

Okay, heres what i did. I had a speed sensor (new) from a 95 f150 which i know is on the diff on a 95. I pulled the sensor from the 97 (off the diff) and it had the same number stamped in it as the one from the 95. I then assumed that it was the speed sensor, but obviously i am mistaken. I just realized that there is another sensor on the tranny a few days ago after you mentoined it in your prevouis post. thanks for clearing this up for me.

 

Good !!! Let us know how you make out ....