Finally had some time to put on this problem.

Thanks to you I found the problem was the pot metal gear slipping, it never occured to me that this would be possible.

In the mean time I found two more defective odometers in my spare parts; one with a plastic gear missing one tooth, the other one having the pot metal gear slipping on the shaft.

As you did I pushed out the shaft and reversed it so the pot metal gear would be thight on a unworn part of the shaft. And I did not want to go back there so I did an extra touch. I put the pot metal gear on a flat steel block and using a 1/4inch pusher I gave it a mild hammer blow in the center so the hole would be smaller, I hoped.

I pushed the shaft back in its position using a vice. Using a variable speed drill on reverse I could confirm the km counter is working ok.

Now I have two odometer spares for this 1982 volvo that has more than 325k miles (525k km), burning no oil (unbelievable). It is now with a front windshield that has the chrome trim replaced with a hand applied black urethane strip, a m46 overfilled transmission and running with a modified electronic ignition from a 1982 b23e. This is a B21A with carburator.

Thank you again Art to put me on the right track.