I have a 1979 280ZX that the speedometer stopped working. I connected the smaller length cable from the back of the speedometer to the firewall (it was disconnected initially). The speedometer needle jumped once, then stopped, and all I get is a clicking noise. I suspect the speedometer has a stripped gear(?). Are there parts that can be bought to fix this issue? Are there other Datsun speedometers that are interchangeable from other Datsun models?