Yamaha - Gear (21T) Lower Unit Gear Component 6CF-45560-01-00. Overview. The Yamaha Gear (21T) 6CF-45560-01-00 is a precision-machined gear designed to ensure smooth and efficient power transfer within your outboard's lower unit. With its 21-tooth configuration, it plays a vital role in maintaining proper gear ratios and consistent propulsion. When gears begin to wear, you may notice grinding noises, slipping, or reduced performance-this component helps restore reliable operation and protects surrounding parts from further damage.. Key Features. • 21-Tooth Gear Design - Optimized for proper gear ratio and smooth power transmission.. • OEM Fit Precision - Manufactured to Yamaha specifications for accurate alignment and seamless integration.. • Reliable Power Transfer - Ensures consistent propulsion and efficient operation.. • High-Strength Construction - Built to withstand torque, pressure, and harsh marine environments.. Engine & Boat Compatibility. Verify compatibility with your speci