Odometer stopped working?

On my way to work this morning the odometer stopped at just over 80,000. The speedo, and tach still work. This happened once before, but only for a few days then started working again. Any idea what causes this, or how to fix?

Did you buy car used? If so how long ago?

If the transmission is anything like the one in my 240 then it is probably the sensor on the transmission end. The 240 has a hard plastic gear that sends a signal to the odo depending on gear and rpms. Sometimes, especially if you are shifting hard, you'll break some teeth off and it will stop working then catch again for a while and so on and so forth. That or it might be a loose connection in the dash.