Yamaha - Gear - Lower Unit Internal Drive Component - 64J-45560-00-00

Overview

When you’re inside a lower unit, gears are where everything either works perfectly—or doesn’t. I’ve seen worn or chipped gears cause everything from noise to complete loss of drive. This Yamaha gear is built to mesh clean and run smooth, which is exactly what you want when putting a gearcase back together. It’s one of those parts you replace right the first time so you don’t have to go back in later.

Key Features

• Precision Gear Cut – Designed for smooth meshing and efficient power transfer.
• OEM Fitment – Matches Yamaha specifications for exact alignment within the gearcase.
• Hardened Metal Construction – Built to handle constant load and high torque conditions.
• Reliable Operation – Helps maintain quiet and consistent lower unit performance.

Engine & Boat Compatibility

Fits Yamaha outboard engines that utilize compatible internal lower unit gearing systems. Commonly used in mid- to high-horsepower applications across offshore boats, bay boats, and recreational vessels.

FAQ

Q: What are signs of a worn or damaged gear?
A: Grinding noise, vibration, or slipping in gear are common signs of gear damage.

Q: Can I replace just one gear or should I replace a set?
A: It’s best to inspect all related gears—uneven wear can cause problems if only one is replaced.

Q: What usually causes gear failure in a lower unit?
A: Low or contaminated gear oil, impact damage, or long-term wear under heavy load.

Q: How important is gear oil maintenance for these parts?
A: It’s critical—clean, properly filled gear oil is what keeps gears lubricated and protected.

Q: Is installing internal gears a difficult job?
A: It requires experience with gearcase assembly and proper shimming, so it’s usually a job for someone familiar with lower units.