I have read the postings on speedometer problems but can't understand how you would tell one problem from another. Shortly after (less than 2 miles)I changed engine oil & filter along with transmission fluid on my 1992 GXE with 99,200 miles both the odometer and Speedometer stopped working completely. How do you determine if problem is speed sensor or speedometer, dealer does not take back electrical parts. If dealer does repair to speedometer does the car get "True Miliage Unknown" title? I would think if the speed sensor was bad you would get a check engine light & code, not to mention rough engine running. Car runs well. Any help would be appreciated.

 

If the problems are with the speedo then the odometer tends to keep working. As I recall the signals pass through the odo first and then into the speedo.

If the odometer has packed in as well then I'd say speed sensor. You might have knocked something getting the oil filter off. Check carefully.

 

if you changed your oil and stuff revently, it's the speed sensor. i bet the same thing happened that happened to mine. the sires of the speed sensor moved and touched the manifold and are now melted and touching together. all you have to do is pull the sensor out unhook it from the harness cut the wires on the good part, get some more wire, crimp the wire on, wrap it with some good heat tape and it works. (that's if the wires did melt like mine did)