Yamaha - Shifter - 6AX-45641-00-00Yamaha Shifter Lower Unit Shift Mechanism 6AX 45641 00 00 Overview Shifting should feel clean and solidno hesitation, no grinding, just straight into gear. When the internal shifter starts wearing out, that smooth feel disappears and youll notice it right away at the helm. This is one of those parts that takes a beating every time you go from neutral to forward or reverse. Yamaha built this shifter to hold up under that constant use and keep your