I installed my new speedo cable and my 20mph bouncing went away... to be replaced by some shaking around 40mph.
In addition, it doesn't register at all until about 15mph when starting out, though it will register 15 down to 0 when slowing down.
The replacement part is not MB, it's "GEMO", made in Germany. A couple of minor external differences, including the ability to pull out the inner cable.
The cable was not turning "silky smooth", so I tried pulling the inner cable out and lubing it with Lithium spray grease, but didn't seem to make any significant difference.
I also tried driving it with the cable hanging in a gentle arc rather than clipped to the transmission to avoid the harshest bend, but same deal.
Should I have sprung for the genuine Mercedes part? Or is my problem elsewhere? Or do these speedos always have a little flakiness to them?