Speedometer Pulses

MY speedometer started pulsing a week or so ago. It would show 10 mph then jump to 40mph, back to 0 mph up to 100 mph ect.
Bought a new cable and installed it, but my speedometer is still pulsing....do I need to replace the inst. cluster now?
If so, any ideas where I can get one?
1976 Mav. w/ 302, AT. Manual Steering and brakes.

 

Did you grease the new cable? If not that should solve your problem.

 

I shot some WD-40 down the cable, will that do, or is there a special lube needed?

 

I think I have an extra instrument cluster, including a speedo (not the bathing suit ) in the attic, just in case you can't get that jump fixed with some lube.

 

No, WD 40 will not work....white lithium lube or any thick grease will work, in fact you can pick up a tube especially for speedometers at the local parts store. I has to be a thick substance in order to work.

 

Lube the cable with a graphite. You can buy a spray can of this at any good auto parts store. Hold the cable up and spray away until you see it coming out the other end. Now your lubed!