Yamaha - Gear 2 - Lower Unit Gearcase Component - 6H3-45571-00-00

Overview

When a lower unit starts making noise or slipping under load, gears are usually where the problem shows up. I’ve opened up gearcases where this gear was worn just enough to cause rough engagement or inconsistent performance. It’s not something you want to ignore, because it only gets worse with use. Replacing it the right way brings the drivetrain back to smooth, reliable operation.

Key Features

• Precision Gear Engagement – Transfers power within the gearcase for smooth and consistent operation.
• Hardened Gear Construction – Built to handle torque and resist wear under continuous use.
• OEM-Spec Machining – Designed to Yamaha tolerances for proper gear mesh and alignment.
• Reliable Power Transfer – Supports steady propulsion without slipping or abnormal noise.
• Critical Drivetrain Component – Essential for proper lower unit function and long-term durability.

Engine & Boat Compatibility

Designed for Yamaha outboards with compatible lower unit and gearcase assemblies. Commonly used on small to mid-size engines found on fishing boats, skiffs, and recreational vessels. Always verify compatibility with your specific engine and gearcase before installation.

FAQ

Q: What are signs this gear is worn or failing?
A: Grinding noise, slipping out of gear, or metal particles in gear oil are common signs.

Q: Can I replace just this gear?
A: Sometimes, but it’s important to inspect the entire gearcase since wear often affects multiple parts.

Q: Is this a difficult repair?
A: Yes, gearcase work requires precise setup, including shimming and alignment.

Q: What causes gear damage in the lower unit?
A: Impact, low or contaminated gear oil, and normal wear over time are the main causes.

Q: Should I replace other components during repair?
A: It’s recommended to check and often replace bearings and seals while the gearcase is apart.