Yamaha - Lower Unit Assembly Drivetrain System 6E0-45300-14-8D. Overview. When a lower unit starts giving trouble, it's usually not something you want to patch together piece by piece. I've seen guys chase noise, slipping, or water intrusion, only to end up replacing the whole unit anyway. A complete assembly like this takes the guesswork out and gets you back on the water faster. Once it's bolted up right, you get that smooth, quiet operation Yamaha lower units are known for.. Key Features. Complete Lower Unit Assembly - Comes fully assembled for straightforward replacement and reduced downtime.. Smooth Power Transfer - Delivers consistent power from the driveshaft to the prop for reliable performance.. Corrosion-Resistant Construction - Built to handle harsh marine environments, including saltwater use.. Direct OEM Replacement Fit - Matches original specifications for proper alignment and seamless installation.. Engine & Boat Compatibility. Designed for Yamaha 2-stroke outboard engin