Yamaha - Lower Unit Assembly - Gearcase & Drive System - LF300 - LF350 - 6AX-45300-3A-8D 

Overview

On Yamaha’s larger offshore motors, the lower unit is doing the heavy lifting every time you throttle up. This assembly is built for LF300 and LF350 platforms, delivering smooth, consistent power transfer from the engine down to the prop. Whether you're running long offshore trips or pushing through rough water, having a solid gearcase underneath matters. If your current unit is worn or starting to show signs of failure, replacing it brings back that confident, steady performance you expect from a Yamaha.

Key Features

• Heavy-Duty Gearcase Assembly – Designed to handle high horsepower loads and offshore use.
• Efficient Power Transfer – Ensures smooth delivery of engine power to the propeller.
• Corrosion-Resistant Build – Built to withstand harsh saltwater and marine conditions.
• OEM Yamaha Fitment – Engineered to factory specs for proper alignment and reliable operation.

Engine & Boat Compatibility

• LF300 - 2007-2009
• LF350 - 2007-2012
• FL350 - 2010

FAQ

Q: What are signs a lower unit needs replacement?
A: Grinding noise, vibration, shifting issues, or water in the gear oil are common indicators.

Q: Is this a complete lower unit assembly?
A: Yes, it’s a full gearcase assembly designed for direct replacement.

Q: Will replacing the lower unit improve performance?
A: If your current unit is worn or damaged, it will restore smooth operation and proper power transfer.

Q: Is installation difficult?
A: It’s a more advanced repair and typically handled by experienced technicians.

Q: Are these updated part numbers?
A: Yes, these assemblies supersede earlier versions while maintaining proper fit and function.

• Supersessions
  6AX-45300-30-8D, 6AX-45300-38-8D, 6AX-45300-39-8D, 6AX-45300-3B-8D, 6AX-45300-3B-8D