I'm supprised nobody mentioned the sensor mounted on top of the ATX that, when it goes bad, does that crazy shiz. Starts shifting into neutral, 2nd gear, drive, whatever. Seemed totally random. THen I found there is a sensor that was bad. Replaced the sensor, and it works great now!

Can't remember what that sensor was called though. Something like, shift selecter sensor? Whatever it is, its the sensor that tells the trans what your shifter is shifted to. Sorry for the lack of a technical description. But the sensor was only like, $35 IIRC.