Speedometer Lube

FWIW, I use speedometer cable lubricant on the cable, white lithium grease for the speedometer itself.

And I wipe off the speedo cable lubricant from the top 2-3 inches of the cable. It's really not meant to lubricate the speedometer itself.

Can't remember where I read all that, but that's the way I've fixed several noisy speedometers.