Yamaha - Gear Lower Unit Gear Train Component 6E7-45560-01-00. Overview. Gears inside the lower unit take a beating, especially if the motor's been run hard or seen a few impacts. I've opened up cases where one worn gear started a chain reaction of noise and vibration. This gear is part of what keeps power moving clean from the engine down to the prop. When it's in good shape, everything runs smooth and quiet like it should.. Key Features. • Precision Gear Tooth Design - Ensures smooth engagement with mating gears for reliable operation.• Consistent Power Transfer - Helps deliver steady torque through the lower unit.• Hardened Metal Construction - Built to handle load, friction, and continuous marine use.• Reduced Wear Performance - Designed for clean meshing to minimize stress on surrounding components.• Exact Yamaha Fitment - Matches factory specifications for proper alignment and installation.. Engine & Boat Compatibility. Designed for Yamaha outboard lower units utilizing internal