Yamaha - Gear 2 Lower Unit Gear Train Component 6E7-45571-00-00. Overview. When you've got the lower unit apart, you quickly realize how much these gears matter. I've seen one worn gear throw off the whole system-noise, vibration, even slipping under load. Gear 2 plays a key role in transferring power smoothly through the case. When it's in good condition, everything meshes clean and the motor runs quiet and strong.. Key Features. • Precision Gear Tooth Design - Ensures smooth engagement with mating gears for reliable operation.• Consistent Torque Transfer - Helps deliver steady power from the engine to the propeller.• Hardened Metal Construction - Built to handle load, friction, and continuous marine use.• Reduced Vibration Operation - Supports smoother gear meshing and quieter performance.• Exact Yamaha Fitment - Matches factory specifications for proper alignment and installation.. Engine & Boat Compatibility. Designed for Yamaha outboard lower units utilizing internal gear train sy