Yamaha - Gear 2 Drivetrain Component 6K5-45571-00-00. Overview. The Yamaha Gear 2 6K5-45571-00-00 is one of those internal parts that keeps everything turning the way it should inside the lower unit. When gears start to wear, you'll usually hear it before anything else-grinding, whining, or that rough feel when under load. This gear plays a direct role in how power is transferred, so it needs to stay sharp and properly meshed. If you're already inside the gearcase, it's worth making sure this piece is solid.. Key Features. • Efficient Power Transfer - Moves engine output smoothly through the lower unit drivetrain.. • Precision Gear Cut - Designed for proper meshing and reduced internal wear.. • High-Load Strength - Handles torque and stress from continuous operation.. • Stable Operation - Helps maintain consistent performance and reduce vibration.. Compatibility. Compatible with select Yamaha outboard engines using this Gear 2 configuration.Typically found in Yamaha lower units requiri