Probably depends on what car it is. Many of the cars had a plastic gear inside the cluster that breaks.
Here's one of a few topics that may help if this is also the LeBaron. http://www.allpar.co...working-analog/
You probably have a late 80's or early 90's vehicle and the speedometer heads made by VDO had poor odometer gears in them that cracked over time. It is possible to replace the odometer gears.... many here have done it, but proceed with caution because it is a bit intricate. It really depends on how far you want to take it yourself and the skills you have with working with small parts. You can search "broken odometer" and find a lot of good stories and experiences on Allpar.