Yamaha - Dog Clutch Gear Engagement Component 6CB-45631-00-00. Overview. The Yamaha Dog Clutch 6CB-45631-00-00 is a critical internal component within the lower unit that enables smooth shifting between forward, neutral, and reverse. It works by locking gears together when engaged, allowing power to transfer efficiently from the engine to the propeller. When this part becomes worn, you may experience gear slipping, grinding noises, or difficulty staying in gear. Replacing it helps restore proper shifting performance and protects other drivetrain components from damage.. Key Features. • Positive Gear Engagement - Locks gears securely for reliable forward and reverse operation.. • OEM Fit Precision - Manufactured to Yamaha specifications for accurate alignment and dependable performance.. • Prevents Gear Slippage - Helps maintain consistent engagement under load.. • Heavy-Duty Construction - Built to withstand torque, shock loads, and harsh marine conditions.. Engine & Boat Compatibility