Yamaha - Gear 1 Assembly Drivetrain Component 6J8-45560-00-00. Overview. The Yamaha Gear 1 Assembly 6J8-45560-00-00 is one of those internal parts that keeps your lower unit running smooth every time you drop it in gear. When gears start to wear, you'll hear it right away-noise, vibration, or that rough feel under load. This assembly handles a big part of the power transfer, so it needs to stay tight and properly aligned. If you're already inside the gearcase, replacing it now saves you from tearing it back apart later.. Key Features. • Complete Gear Assembly - Includes matched components for consistent drivetrain performance.. • Smooth Gear Operation - Helps reduce noise and maintain clean power transfer.. • Precision Machined Fit - Designed for proper alignment inside the lower unit housing.. • High-Load Durability - Built to withstand torque and continuous use on the water.. Compatibility. Compatible with select Yamaha outboard engines using this Gear 1 assembly configuration.Common