Finally got my hands on a spare instrument cluster for my 83 with odometer broken for over a decade. With this I was willing to try the surgery described on Dave Barton's page. Like him, I discovered my inner, lead gear was spinning on the shaft and replaced it. I also saw what looked like hairline cracks in the 14 tooth outer gear. They might have just been mold marks from their original creation. But I decided to go "whole-hog" and replaced that too. Dave's instructions were really quite good. A little weak when dealing with how to press the new gears onto the shaft but I figure that out using a channel lock pliers and some small plastic "tubes" I had lying around. One thing I discovered is that I was able to test the thing, once assembled but not yet in the car, by using a drill with a number 1 square drive drill-driver bit inserted into the speedo cable connector. Run the drill in reverse. See the odometer trip meter move and after a mile see the main odometer move. Also not the speedo responds to drill speed changes and stays constant once the drill reaches max speed. Cool!