Here's an earlier post:
Your broken odometer and "jumpy" speedo needle are unrelated (i.e., due to separate causes and requiring different solutions).
A broken mechanical VDO odometer is usually the result of trying to reset the odo when the car is moving - this will shear the right-most wheel from the shaft. And it is this wheel that drives the whole counter. So lesson one is that when you do get it fixed, reset your odo ONLY when at a stop. Fortunately, you can easily fix it yourself by re-securing that right-hand wheel - either by scoring the shaft a la WDurrance (above) or with an anaerobic adhesive. Unlike super glues and most other adhesives this type will not creep through the adjoining air space to the other wheels. (You only want to glue the right-most wheel!) I prefer the adhesive technique in terms of ease and durability, but be sure to use the appropriate product (Loctite Sleeve Retainer #620 is my choice).
When you do this, or any other job requiring removal of the instrument cluster, be careful not to jam or bend the speedo cable. After ensuring that the cable is routed loosely, a trembling speedo needle can usually be cured by lubricating the inside of the cable where it connects to the cluster. (Use generous shots of Kable-Ease cable lubricant, or similar.) It may only be that the bushings have dried out. If that doesn't work then the cable has been damaged and needs to be replaced.