Saab Repair: 93 Saab 9000 CSE, saab 9000, speed sensor

Question
I purchased a used 9000 CSE Saab and the speedometer has stopped working. What could be the problem be. I noticed it late last night I have not checked to see if the odometer is working or not.

Answer
There is a speed sensor mounted on the top of the transmission. These sensors can fail. The usual culprit however is usually the plastic gear in the trans that drive this sensor. Remove the sensor and spin the shaft while having someone watch the speedometer, if the speedo moves the gear in the trans is likely at fault. If it doesn't then likely the sensor is bad. You may need to use a drill to spin the shaft of the sensor fast enough to see the speedo move.