what does the 4 prong sensor on the drivers side of the trans do? reason I am asking is because I just put a new trans in and the plug on my harness did not fit into the sensor on the trans. I had to use the one out of my old trans. The difference was that the new one only had 3 prongs and 3 wires in the trans. My old one had 4 prongs. The harness inside the valve body hooked up to the sensor fine it just didnt have 4 wires like the old one...