Hi all. What would most likely cause the speedo needle to wiggle. It will go up to about 30mph then back to 25 mph. Back and forth all the time. 30 is the about the max the speedo will go. Put a new speedo in and still have the same issue.
Its a '41 1 1/2 ton 4 speed

Thanks

Andy

Sometimes you're the window
Sometimes you're the bug