Hi Bill, from Durham Effectively my speedometer as an electronic connection to a sensor located on the differencial cover. However I obtained an exploded view of the differencial and it seems that the sensor is on the back cover of the differencial (back side of the car on the opposite side of the f...

The speedometer of my volvo 960 summum, 3l,24v, 1991 is occasionally unstable. While running at 120 KM/h, the reading may vary from 0 to 160 very erratically.
Do you have some clue about the origin of this problem: wiring, sensor, electronic?
Thanks for your help