I've taken the speedometer/odometer out of my 84 300SD because the odometer stopped working. The speedometer works fine. It started making a clicking noise a couple of months ago which varied according to the speed of the car. Now there is no clicking and odometer doesn't spin.

The speedo/odometer on my SD appears to be electronic. There is a six pin connection as well as what I thought was a mechanical cable that uses a twist friction connection (this, I thought was the cable from the transmission that turns the gears in the speedometer/odo). But after removing the back cover of the speedo/odo and examining the shaft, the shaft is fixed and connects solidly to the circuit board, so the cable that I thought was mechanical appears to be a wire that sends electric impulses to the speedometer to indicate speed and and spins the odometer.

Anyway, the shaft of the odometer and gears on it does not appear to be like the one described on this thread. The shaft of the odometer numbers is covered by a clear plastic housing that looks like if removed, everything will fall apart and I'll have a mess on my hands. Any ideas on what I can do to repair the odometer on my 300SD?

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Rob
'84 300SD 258K
'85 300D (sold)