My 55 Crown had a similar problem (and, I've worked on several others in the past): You can take it apart; but, be very careful! Generally, that noise and the needle jumping is caused by a dry bushing internally to the speedo. The only way to get to it is by taking it apart: it's a support bushing under the "motor" (a funny-looking 1-1/2" diameter? flattish-round cannister that is magnetized).
After 53 years, it deserves some tender loving care! Solvent-clean (MEK, etc.; but, DON'T get any solvent on any of the plastic gears, guage face, etc.), then re-lube with a very light machine oil & you'll likely be all set for another 50 years. You may also want to carefully lube the odometer gears & bushings. If you're mechanically-inclined, you also have the opportunity to re-set the odometer, if desired; though, to some people, that might be "cheating".
Thanks, JLB
55 Ford Crown Victoria Steel Top