Yamaha - Gear - 68T-45560-00-00Yamaha Gear Lower Unit Drivetrain Component 68T 45560 00 00 Overview Gears like this are what keep everything moving smoothly when youre pushing the boat hard. Its buried in the lower unit, but its constantly taking load every time you throttle up or shift under power. When its in good shape, you dont hear or feel a thingjust smooth acceleration. When it starts to go, youll notice noise or roughness pretty quickly, especially under load. Key Features