Yamaha - Gear 2 (28 Tooth) Lower Unit Gear Train 6EH-45571-00-00. Overview. When you open up a lower unit and find worn or chipped gears, it's never a small job-but it's one that has to be done right. This gear is part of what keeps power moving cleanly from the driveshaft down to the prop. I've seen even minor wear here turn into noise, slipping, or worse if it's ignored. With a solid gear back in place, everything runs quieter and smoother like it should.. Key Features. • 28 Tooth Gear Design - Precisely cut teeth ensure proper engagement within the gear train.• Smooth Power Transmission - Helps deliver consistent torque through the lower unit.• Hardened Metal Construction - Built to handle load, friction, and long-term operation.• Reliable Gear Engagement - Supports clean meshing with adjacent gears to reduce wear.• Exact Yamaha Fitment - Designed to match factory specifications for proper alignment and function.. Engine & Boat Compatibility. Designed for Yamaha outboard lower units