[Model A Ron]

I took the speedometer out and it works just fine when I tested it so I put it back in the car. Then I jacked the car up and looked at the cable in the car. It was not turning with the car in gear but when I applied a little pressure and pushed it in it started to turn. I know some have said to add a nail to the transmission gear but I do not understand how this looks or how to do it. Can someone post a photo of the fix with the nail? I am sure it works but I cannot visualize it.

Thanks
Ron