1992 240 Speedometer & Odometer not working

[my240]

I just removed and re-installed the instrument cluster on my 1992 240 wagon in order to replace the blower motor. The speedometer and odometer now do not work. They worked before removal of the instrument cluster. I have checked the sensor signal and get good voltage from the sensor in the differential so the problem may in the head. All wires are properly connected and all other gauges and lights on the instrument cluster work. Can you suggest some things for me to check in the speedometer/odometer head? The car has only 60,0000 miles so I am ruling out the gears in the odometer. I have checked the wiring and find no obvious problems. Where should I go from here? Thank you.