could be a number of things. the automatic transmission is messed up. (obviously) what you should do is find a used one on eBay or a local dealer, and if you know how, replace it yourself. they are pretty cheap used, and generally don't have any issues, but its probly ur timing chain or automatic shifter.
Or it can be your speed senor, it could be the cluster in the dash who's knows until you get it
check out you're guessing.
Bad speed sensor.
The speedometer and transmission issues in a 2003 Pontiac Grand Prix could be caused by a malfunctioning vehicle speed sensor (VSS), which provides speed data to the speedometer and transmission control module. Additionally, a faulty wiring connection or a blown fuse could disrupt the signal. Another possibility is a problem with the transmission control module itself, which could prevent the transmission from shifting properly. It's advisable to diagnose the issue with a scan tool to check for error codes related to these components.
Trans output speed sensor.
according to the owners manual this could be related to a problem with the ABS. I have the same problem and am looking for a diy solution. also from the owners manual the ABS controls the transmission , and my transmission is shifting roughly, which is what I noticed before I noticed that the speedometer wasn't working.
The odometer and speedometer not working, along with transmission shifting issues on a 1995 Ford Bronco, could be caused by a malfunctioning Vehicle Speed Sensor (VSS), which provides speed data to both the speedometer and the transmission control module. Additionally, issues with the wiring or connectors related to the VSS, or a failing instrument cluster, could also contribute to these problems. Lastly, low transmission fluid levels or a failing transmission could further complicate shifting performance.
we had to replace the speed sensor in mine and it corrected the problem with the speedometer and the shifting. Good luck
If the speedometer is not working but the odometer is, I would suspect the dash cluster is at fault. If both speedometer and odometer are not working I would suspect the speed sensor on the transmission is at fault.
Speedometer flat. This may be affecting transmission.
You need to replace the speed sensor. It sends a signal to the speedometer and also sends a signal to the transmission on when it should shift.
Could be your speed sensor on your transmission
check your speedometer sensor located back left of engine bay on top of the transmission
If the spedometer is not working and the traansmision will not shift out of second it means the speed sensor is bad, unpluged or the wiring for it is damaged. The shif6ts are controled by the ECM (computer) and if does not know the speed of the car, it will not shift.