Hey Ford truck folks, my 1997 f150 when I put her in drive the speedometer goes up to aproxx 36 mph and stays there no matter what I do or how fast I drive and then slowly falls back to zero when I shut the truck down. Where can I start, I had someone look at it years ago and the said the cluster was bad but I am not sold on that HELP PLEASE I now live in a state that requires an inspection, I use my GPS to tell me the speed I am going, everything else works in the cluster.

 

In your year I believe you have a speed sensor in the trans that has a cable up to the dash.
In the dash is electronics that converts the sensor signal to drive the analog meter.
Inspect the drive gear.
Check the sensor for output with either a low volt AC meter or a counter by turning the sensor . It has no output unless rotating.
Be sure the cable is good.
Then it's cluster time if no issues are found.
If there is no speed reading in Park or Neutral and setting still but in gear and moving, it tells you the sensor and gear is working or there would be no signal to the dash cluster. Verify by removing the cable from the transmission or the sensor plugup whichever it has.
Logic is the key.
Good luck.

 

Thanks I will start there hopefully will get a chance this week