Clucking Speedo

[Short 3/4]

My dashboard is starting to sound like a hen house. Speedometer and odometer otherwise work fine and are accurate, it's just the noise that is driving me crazy. Disconnected the speedo cable and noise went away, also inner part of cable looks good and still has plenty of goo on it. I'm sure the speedo itself is either worn out or dry. Started to take apart an old one I had laying around, but looks like lots of potential for making things worse trying to "fix" it.
Anybody have any luck with one of these, or do I just bite the bullet and buy a new one? The other question of course is if a rebuilt original is better than a new repo as is the case with so many of our parts these days.
Thanks for any help or opinions,
Tom