Bought this and installed. Oiled it as well before the install. It is still jumping around then just drops off. The next time I drive it, it does the same thing. Jumps around then drops off. I have changed the instrument cluster just to see if it was the speedometer itself. It was not. It's doing the same thing. The car is an 88 automatic 5.0 LX. Is the cable adjustable on the end of is it fixed. I'm out of ideas. Can anyone help. I have even called LMR and asked.
I would suggest inspecting the teeth on the gear as well as the drive gear, and as Scott mentioned, inspect the VSS if the car has cruise. It sounds like you have isolated the issue down to one of those components.