Yamaha - Lower Unit Assembly - Gearcase & Power Transfer - 64F-45300-01-8D

Overview

On these older 225 Yamahas, the lower unit is usually the first place you’ll notice wear after years of use. I’ve worked on a lot of them where the gears start getting noisy or shifting just isn’t as clean anymore. Dropping in a complete assembly like this brings everything back to solid, dependable operation. It’s the kind of replacement that makes the motor feel strong and smooth again, especially under load.

Key Features

• Complete Gearcase Assembly – Includes internal gears and housing for a full lower unit replacement.
• Smooth Power Transfer – Delivers consistent engine output to the propeller.
• Heavy-Duty Construction – Built to handle high horsepower loads and long-term marine use.
• Reliable Gear Engagement – Provides clean shifting with reduced noise and vibration.

Engine & Boat Compatibility

225TLRV – 1997

FAQ

Q: What are signs my lower unit needs replacing?
A: Grinding noise, slipping gears, water in gear oil, or rough shifting are common signs.

Q: Can I keep running if the lower unit is making noise?
A: It’s not recommended—damage can get worse quickly and lead to full failure.

Q: Do I need to check gear oil before using this unit?
A: Yes, always confirm proper gear oil level before running.

Q: How does saltwater affect this lower unit over time?
A: Salt can cause corrosion and wear, especially around seals, so regular flushing helps extend its life.

Q: Is installation something I can do myself?
A: If you’ve done lower unit swaps before, it’s manageable, but proper alignment and torque are important.

• Supersessions
  64F-45300-00-8D, 64F-45300-00-4D