My odometer stopped working but my speedometer is still working. Where should I look to fix my problem?

A well known fault, the odometer gears are made out of cheese and crumble They are available but they can be expensive. However if you are reasonably handy look here for a $6.00 solution.https://www.k100-forum.com/t16244-rebuilding-a-k-odometer-using-inexpensive-eby-gears-a-rough-guide
Regards Martin.

Thanks I'll pull the instrument panel apart tomorrow

I had a talk with an industrial Chemist and the OEM gears should not be greased which they originally were. The grease over time caused the plastic to turn into cheese ( Non Edible Tasty). The $6.00 plastic gear assortment contain PTFE and do not require lubrication.
Regards Martin.

I got a set of the cheapo gears from Ali-something. Waste of about $7.00 as the package doesnt have the right sizes. Shop around and get the right ones.