I have a 1996 F150 4 wheel drive 5.8L. My speedometer is not working and it shifts hard while driving. I have replaced the VSS and no change. Any thoughts? I checked the wiring underneath and it appears to be in good shape.

 

If you only looked at the wiring you only wasted some time. You didn't do anything towards fixing this. You need to check the wiring electrically. If it checks out, then suspect the PSOM module on the back of the speedometer.

 

can you elaborate?
What do I need to check?

 

You need to check both wires to the VSS from one end to the other for continuity, short to power, and short to ground.

 

Check fuses #8 and 18 if the speedometer is not powering up. Search the forum as there are 100's of this problem and answers on here.

 

Checked all the wiring and fuses. All good. Ordered used speedo off EBay and installed it. It worked, odometer worked. Road test and damn speedometer started bouncing around 40 MPH. Shifting and everything back to normal. of course can't find another replacement speedo. Any suggestions on that or would you have the original fixed at one of these places that fixes them? Tried junk yards around but nothing that would match.