Just looking for some advice on a problem i have been having with my 1994 f150. 5.8L my speedometer. Quit working and at the same time the transmission shifts hard only in drive or reverse auto. Sometimes the speedometer. Works fine and it shifts perfect as well. Does anybody know anything about why or what may be causing this problem thanks for any help.

 

The ABS wheel speed sensor (located on top of the rear differential) solved the same problems my truck had.

 

Check if your interior light has power when your speedo acts up.

 

What Phil said it's the speed sensor mine was called VSS Vehicle Speed Sensor cost me $20 something and it's plug and play. Make sure you connect it snug and all the way on. was hard to see and I didn't quite have it on all the way it happens. But my speedo jumped around sometimes and also hard shifts fixed it right up brother cheep fix. The wiring for our trucks goes from the VSS to the speedo then to the PCM thats why it messes up your speedo aswell.

 

Thanks for the correct nomenclature, Chris. I was definitely having a senior moment that night!