1995 Buick Park Avenue base.
Engine Size : 3.8 v6.
Speedometer has stopped working and car will not shift out of 1st gear. i replaced the vss and that did the trick for about 3 months and it is at it again. this always happens when it is damp outside. i have checked and cleaned the connections. all i can figure is a short somewhere or a bad module. any ideas? is this a common problem with the 4t60? thanks!

Answer: If the problem comes and goes, and is relate to the weather, then you either have a wiring problem or a computer (ECM) problem. Be sure you check the wires at the VSS connector very carefully. Pull on each one to see if the colored insulation stretches. This would show the copper wire is broken inside that insulation. You could try tapping on the ECM when the car is driver to see if it will act up. Other than that, a resistance check on the wires from the ECM to the sensor while pulling on the wiring would be needed to find the problem wire.