I have a 2002 Jetta 2.0 that wouldn't shift into overdrive. We changed a speed shift sensor, it didn't fix it. Come to find out, there's a speed shift sensor on top of the transmission under the transmission mount. It has a cord with a plug in attached to it, where as the other speed shift sensors don't have a cord connected to them. This fixes it. You also have to reset the transmission computer afterwards. So to do that turn the key in the on position without starting the car. Then hold down the gas petal for 30 seconds. That's it, good it go!!