Yamaha - Gear 2 (21 Tooth) - Lower Unit Gear Component - 6CB-45571-00-00

Overview

This is one of those parts you don’t think about—until the lower unit starts acting up. The Yamaha Gear 2 (21 Tooth) sits deep inside the gearcase, handling load transfer and helping keep everything turning smoothly under power. When it wears, you’ll hear it before you see it—grinding, slipping, or just not feeling right under throttle. Swapping it out restores that solid, confident feel when you drop it into gear and get moving.

Key Features

• 21-Tooth Gear Design – Engineered to maintain proper gear ratio and smooth power transfer.

• Precision Machined Teeth – Ensures clean engagement and reduces internal wear.

• OEM Fit Accuracy – Matches Yamaha factory specs for proper alignment and performance.

• High Strength Material – Built to handle torque, shock loads, and harsh marine use.

Engine & Boat Compatibility

Verify compatibility with your specific Yamaha outboard model and part number before installation.

FAQs

Q1: What are signs this gear is worn out?
A: Grinding noise, slipping under load, or rough shifting are the most common signs.

Q2: Can I replace just this gear instead of the full set?
A: You can, but if other gears show wear, replacing the full set is often the better long-term move.

Q3: Will bad gear oil cause this to fail?
A: Yes, contaminated or low gear oil is one of the fastest ways to wear out internal gears.

Q4: Is this something I can install myself?
A: It requires full lower unit disassembly, so it’s best handled if you’re comfortable with gearcase work.

Q5: Does saltwater use affect this part?
A: Indirectly—saltwater can impact seals and oil condition, which then affects gear life.