[luminacrazy]

To recap my problem, I recently replaced the speed sensor on the 4 speed transmission because the vehicle was showing an inaccurate miles per hour, however the transmission appeared to otherwise shift correctly.

I went to a GM Dealer that I sometimes use for service on my late model vehicle and I got a GM service tech to give me some clues to the shifting problem. He said that under the shift sensor is something called a "Reluctor" which looks like a gear mounted on a rod with a vinyl gear on the other end which turns at the speed of the vehicle.

When operating correctly the reluctor turns with the vehicle transmission speed and the sensor picks up the speed of the vehicle through the turning gear teeth passing by the speed sensor. Apparently on high milage vehicles the vinyl gear on the drive end wears out, he called "Apple Coring" which results in the vehile not showing any speed on the speedometer, and the vehicle being stuck in 2nd gear. He said that I most likley damaged a lead going to a knock sensor, and like the genleman that replied said, it most likley is not causing the shifting issue.

Mr Goodwrench suggested that I remove the Reluctor and see if this vinyl gear is worn out and replace it if it has apple coring. He said that GM service manuals are very bad about showing wiring diagrams and that I should go to a junk yard and get a wire lead end for that knock sensor that I damaged. I suspect he is correct because the car has over 333,000 miles with the origional transmission and engine.

Also that sensor that I purchased from Autozone may have hung up the reluctor from turning properly and if the reluctor did not have apple coring at the time it mostly likley will have it now from the tight fit of the bad part.

The problem with my vehicle and the "Reluctor" is probably why GM decided to change the speed sensor on the 1991 Lumina.