My 150 mph speedometer (1971 Z28 Camaro), began clicking with needle bounce, then stopped working. Now it appears to work correctly up to about 40 mph, then falls back to 0 mph. Anyway, I'm going to pull the speedo out, but need a recommendation as to where to send it for repair. The gauge face is in great condition, just needs the mechanism fixed I think. I know of "Gauge Marks" but don't know if they do repairs to mechanism. Also know of "Tachman" as a possibility. Thanks for suggestions.
If its not slipping on the speedometer transmission gear .The I would check the speedometer have it repaired and or replaced.
Did you try turning one end while watching the other on the cable? I've seen them break but still press the pieces together so they still work, sort of. It may also just need lubricating.
Is the clip at the speedo end clipped over the metal housing at the end of the cable? If you end up pulling the speedo, put a small drop of light oil at all points where the axle for the needle passes through any brackets. Then spin the speedo with a drill, and see if the needle moves properly. There is a tiny bit of slack in the axle, so make sure it's not binding at those points. I'd try this before sending it out. Dale