I have a 2001 Pontiac grand prix GT with 119500 miles. Since last week my speedometer is acting crazy and the transmission won't shift past 1st gear. I suppose the Vehicle speed sensors are gone bad, my car has two speed sensors, transmission input speed sensor is inside the transmission, side cover has to come off to change the $20 sensor, while there I can ask the mechanic to change all the solenoids but is it better to rebuild the transmission rather than just changing all the transmission sensors.