I am rebuilding the dash in my 70 SS Convertible Chevelle. The thousand and ten thousand wheels on the Odometer keep dropping down. There is a plastic piece that keeps all the wheels in alignment that is torn. When I got the car, it showed 79k miles on it. Then this summer the wheels dropped and it went up to 92k miles. When I realigned the wheels, it went back to 69k miles. Now I'm not sure what the original miles are. The speedo is part number 6496643W, built on July 21 1970 and is in excellent shape other than the issue with the wheels. Is it something that can be repaired or should I just live with it? I would really like to avoid having to replace this piece it.