Once again, Art, GREAT photo.

Years ago, before Google could solve any problem, I repaired two VDO odometers with cracked pinions - one on a 240 and the other a Vanagon Syncro with a similar set up.

In order to close the crack, I pressed a collar onto the gear hub. The collar was cut and de-burred from a length of brass tubing which was sized (luckily) to form an interference fit on the hub. Then, I gingerly serrated the gear shaft with a pair of dykes and pressed the gear onto it. I couldn't possibly remember the exact size, but the tubing was the miniature type found in hobby shops, K&S brand.

It was fussy work, but in both cases, the repair lasted all the rest of the miles I cared to put on the vehicles.

Rich (Near Pittsburgh)