Yamaha - Gear - Lower Unit Component - 66T-45560-01-00

Overview

When you’re dealing with the lower unit, gears are where the real work happens. This is what transfers power from the engine down to the prop, and if something’s off here, you’ll feel it right away. I’ve torn down units where worn gears caused noise, slipping, or rough shifting—it doesn’t take much. Keeping a solid gear in place is key to making sure your motor runs smooth and puts power down the way it should.

Key Features

• Power Transfer Performance – Helps deliver engine power efficiently to the propeller.
• Precision Cut Teeth – Designed for smooth engagement and reduced wear.
• High-Strength Construction – Built to handle load, torque, and continuous operation.
• Direct Fit Replacement – Matches Yamaha specifications for proper installation and alignment.
• Supports Smooth Operation – Helps maintain reliable shifting and drivetrain performance.

Engine & Boat Compatibility

• Designed for Yamaha outboard engines with gear-driven lower units
• Compatible with a range of small to mid-range horsepower models
• Suitable for both freshwater and saltwater use
• Commonly used in lower unit repair and rebuild applications

FAQ

Q: What are the signs of a worn or damaged gear?
A: Grinding noise, slipping under load, or rough shifting are common signs of gear wear.

Q: Can I replace just one gear or should I replace a set?
A: It’s often best to inspect the full gear set and replace matching components if there’s wear.

Q: What causes gear damage in the lower unit?
A: Lack of lubrication, water intrusion, or impact with debris can all lead to damage.

Q: Is this a difficult repair to handle myself?
A: Gear work can be complex, so it’s usually recommended for experienced mechanics.

Q: Does saltwater use affect internal gears?
A: Indirectly—proper sealing and gear oil maintenance are key to preventing corrosion.

• Supersessions
  66T-45560-00-00