I've pulled the cluster out of my '84 300SD to repair an intermittent clock. I would like a bit of guidance before I get into it.

My clock works sometimes, but it appears that whether it works or not depends on the position of the knob used to adjust the time. I haven't completely disassembled the clock/tach portion of the cluster, so I don't quite know what I need to be looking at. When the clock stops working, and I re-set the time via the knob, if I'm very careful with how I handle the knob, it will work for weeks on end. Could it be that this is just a coincidence and that the capacitors are actually the problem?

Also, my speedometer and odometer appear to both be reading about 10% too fast, but they work very well. The gears are in good shape, but I don't know why they would both read too fast. I bought the car used, and it has a brand-newly rebuilt transmission from Sun Valley Transmissions (mercedesdismantlers.com). I'm using factory-sized tires (195/70R14), so it's not a tire-size issue. I have two other used clusters, and both of those read 10% too fast also. Could it be that the drive/pickup from the transmission is incorrect?

Any help is greatly appreciated.

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1984 300SD
351,000 miles