Yamaha - Gear 2 Lower Unit Drivetrain Component 6L2-45571-00-00. Overview. When the second gear in the lower unit starts to wear, you'll feel it in how the motor carries load and shifts under pressure. It's not always obvious at first, but over time it leads to noise and inconsistent performance. I've seen setups where everything else looked fine, but this gear was the weak link. Replacing it brings the drivetrain back to smooth, reliable operation you can count on.. Key Features. Precision Gear Engagement - Designed for smooth interaction with mating gears under load.. High-Strength Material - Built to handle continuous torque without premature wear.. Factory-Spec Machining - Ensures proper fit and alignment within the lower unit.. Restores Smooth Operation - Helps eliminate noise and uneven power delivery.. Durable Wear Surface - Engineered to withstand constant contact and rotation.. Engine & Boat Compatibility. Designed for Yamaha outboard engines with compatible lower unit gear sy