That is a great rear hub! Bendix 2-speed automatic (kickback). If working correctly, slightly pedal backwards, then forward again. The hub should shift between high and low gear ( drive and underdrive). Im sure there is a link on here to clean and grease it. Assembly and reassembly must be done a certain way, damage will occure if not correctly executed! The index spring is the most fragile part, and not easy to find a replacement.
Johnny