When I first started having these problems, I too assumed that it was the cable but it wasn't.
Brad: That's EXACTLY what happened to me in my 62. I was driving to San Antonio to pick up my new Harley. Got an early start and the damned speedo began GOING ABSOLUTELY NUTS, screeching and pegging. It has made noise before (not as bad though) then it would quit so I was hoping that it would stop. It didn't... I finally had to pull over and disconnect the cable. The needle broke and I had to replace the entire unit. Now when I see an old truck, the first thing that I do is pilfer the dash contents.
