Speedometer bouncing

72 Dart picked up another cluster to replace mine which has several broken pins, wanted to check speedometer using a drill and the needle bounces all over the place anything I can check to fix it? Doesn't seem to be anything wrong that I can see
Thanks

View attachment 1715617976

View attachment 1715617977
May be you damaged something when you spun the odometer back to zero. :poke::poke: