[Slowmotoring]

I had the same issue on my 29 tudor. I found where the cable goes into the speedometer there is a small piece of tin between the cable and the part that spins where the cable goes in. My tin piece ended up getting rounded some and stopped working. I was able to pull out the tin piece with needle nose pliers and turn it around so the end that was originally in first is now facing out since it was in better shape than the other end. Not sure if all speedometers have this tin piece or not but thats how i got mine going again. I also removed the back cover of the speedometer and applied small amount of oil on the gears to help things move freely.