All this talk about - Genuine Mileage - Clock Repair - Cruise Control etc reminded me of a problem I had in my car which was part of the overall rebuild of the instruments.
The odometer didn't work and the fix is quite simple and very elegant but takes a fine touch with a small toothpick and the smallest amount of Blue loctite.
Here is the website used http://articles.mbz.org/instrument/odo/ (http://articles.mbz.org/instrument/odo/)
There is also a more comprehensive listing in a new article at the same sitehttp://articles.mbz.org/instrument/odo2/ (http://articles.mbz.org/instrument/odo2/)
The first attempt I made managed to glue the first two gears together but the second attempt has held up for 2 1/2 years.
Replacing the Speedo Cable also gave a rock steady speedo needle - especially at low speeds.
Bill
Looking for the articles referenced in the post below. They point to mbz.org which seems to no longer exist. Are they stored elsewhere or is there similar elasewhere?
Here is are links for odometer repair and also clock repair:
https://www.ifixit.com/Guide/Repairing+Mercedes+W123+Odometer/25421
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1383540-1984-mercedes-300dt-clock-repair.html