I had that same 190 odometer problem recently, and stumbled on this old thread. Like haasman said, I pushed the white 16-tooth pinion gear inward to engage properly again with the worm drive. Except my gear wasn't slipping on the metal shaft. The entire 3-inch shaft slid back to where it belongs, with the far end going back into an alignment hole that straightened the odometer numbers again. The worm drive rotation direction is such that it pulls the shaft outward if the worm-to-pinion contact gets sticky. Worrisome that the shaft needs to drive a pot-metal gear at the units-end of the odometer numbers. Hope there's enough friction remaining in this press-fit to keep the numbers turning for several more years. The instrument cluster is a real pain to pull and reinstall, with all those connections behind it.