Questions and Answers

Pontiac 6000 Speedometer Quit Q. I have a 1987 Pontiac 6000, 2.5 liter engine, automatic transmission and approximately 115,000 miles. The speedometer just quit a month ago and now will jump occasionally when taking off, up to 10 mph. Does it run on computer or gear? We can't seem to find what the problem is. Thank you in advance for any help you can provide! Sincerely, Theresa

A. There is a sensor inside the transmission that sends a signal to the ECM and then to the dash cluster. This sensor is driven by a gear on the output shaft of the transmission. The driven gear could be cracked and spinning instead of driving the sensor. The sensor could be bad or the wires to it may be bad.

Rear Of Engine, Top RH Side Of Transaxle