Try hooking a variable speed power drill to different places in the system. Maybe this will help locate the bad spot. The bouncing needle syndrome is often caused by a cable that could use some grease on it (read warning below) or from a cable that is slightly too long for it's tube. When the cable whips around, the needle bounces. Greasing a speedometer cable is not always a good idea since grease can migrate into places where you don't want it such as inside of your speedometer. Grease on the lower cable may not be a bad idea. Wheel bearing grease is pretty thick and does not migrate much. I'm sure other people on this list will tell you that greasing any part of the system (except the angle drive) is a bad idea, so take this advice with a grain of salt. Walt Tampa, FL