Hey out there, not sure what thread to post so hopefully someone will give their insight.
Have a 88 Cultass Supreme Classic that been sitting since 2006.
The speedometer needle works but has a clicking sound with the needle jumping a little bit each time in clicks and the odometer meter does not turn the numbers to increase the mileage.
I unhooked speedometer cable to cluster and unhooked the short speedometer cable that was attached to the long cable that goes to the transmission and cleaned them both.
Still does the same thing are assembling.
Is the problem in the rally gauge itself or where the cable hooks into the transmission? Since it's a 80,000 original mile car I'd certainly like the odometer to turn.
Thank you for anyone's input.

 

As a comparison that may not serve as a solution to your problem, I pulled the cable from the sheath on my '70 442 and lubricated it well. The needle quit jumping around and things seem normal now. I did the same thing on my '57 Ford and the speedometer needle still jumped around like crazy. I sent that speedometer off for repair. Needed a jewel according to the guy doing the work. No more problems.

Now, I realize your 88 Cutlass speedometer may not be built using jewel technology, and you stated you cleaned things, but did you lubricate? If you lubricated then you may need professional help. Perhaps others have something else to add. Happy Motoring!