Speedometer jumping, and inaccurate

My issues in this area come from: 1. Cable not fully seated in transmission pinion and in the speedometer head. 2. Lubrication of speedometer cable.

1. Tough to solve with the plastic clip on the back of the speedometer. It will connect without having the cable completely seated in the speedometer. If you can rotate the cable with your fingers and the car is stopped, suspect a broken speedo cable, or cable not seated firmly in transmission pinion.

2. I get powdered graphite at a locksmith for lubing the cable. It can be messy and don't sneeze. It avoids the problems of moisture and liquid lubricants. For maximum effectiveness, puff into cable at speedometer end.