We have just install a manual saginaw 4-speed into our 1981 Chevy Silverado. This transmission has two senders on it. One is the backup light sender. Does anyone know what the other sender would be? Its located on the bottom. Our old 75 Vega had a neutral light sender, could this be one? We have not a clue what this tranny came out of, we were told it was from a truck, and since the shifter came attached and threaded perfectly up through the floor, we believe it. It works great without anything hooked up to this odd sensor, but would like to know what we are missing.