Yamaha - Dog Clutch Gear Engagement Component 6D8-45631-00-00. Overview. The Yamaha Dog Clutch 6D8-45631-00-00 is a critical component inside the lower unit that enables smooth and reliable shifting between forward, neutral, and reverse. It works by locking gears together when engaged, allowing power to transfer from the engine to the propeller. When this part begins to wear, you may notice gear slippage, grinding noises, or difficulty staying in gear. Replacing a worn dog clutch is essential to restore proper shifting and prevent further damage to internal gear components.. Key Features. • Positive Gear Engagement - Locks gears together for dependable forward and reverse operation.. • OEM Fit Precision - Manufactured to Yamaha specifications for accurate alignment and reliable 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 Compatib