What I learned about odometer repair on my 300SD. I purchased the car in 08 odometer not working I sent whole speedometer to a repair company down South that specialize in this area they asked what milage I want on it and do I want mine back or a different one for quicker return. I said it give me quick turn around. I think I was charged about $140 but not sure any way it stopped working again about 4 yrs. later. I did some research on this site and learned there are 4 plastic teeth gears in there that tend to get stripped I bought the kit that comes with 3 and the # of teeth can vary so you have to count your teeth 2 of the gears are double teethed inside and out freewheeling on the shaft and the drive gear 12 teeth is pressed on not freewheeling. I ordered the kit for $37 dollars and am glad I did at the time I replaced the 2 free wheeling ones but the drive gear looked fine so left it alone. Well last week odometer failed again took apart and saw drive gear was shot all chewed up luckily I found my one from previous repair but as I looked at it could not figure how it was going to fit on shaft. I then read there is a small brass collar that the original gear was on that you have to remove with a wire cutting plier before you press the small replacement 12 tooth gear on. Well put it all together every thing worked except I had no radio and no cluster lights and no outside temp. readout light because when pulling out the cluster I shorted a hot wire feeding my clock and blew fuse 9 in fuse panel and blew the small 2 watt bulb in the temp. readout. The other 2 cluster lights were not on because the dimmer was turned down which I did not realize. Took the temp. board and had the small bulb which was hard soldered in to the board replaced at a local electronics store for $5. All is well now hope this helps someone that runs into same problem.