Yamaha - Lower Unit Assembly Outboard Drivetrain 6L2-45300-14-8D. Overview. When a lower unit is in good shape, you don't think about it-it just shifts clean and runs smooth. But once it starts wearing out, everything from shifting to overall performance takes a hit. This Yamaha assembly is the kind of replacement that brings things back to that solid, dependable feel. It's built right, fits the way it should, and gives you confidence every time you put it in gear.. Key Features. Consistent Power Delivery - Transfers engine output smoothly to the propeller with minimal vibration.. Corrosion-Resistant Housing - Built to handle harsh marine environments, including saltwater use.. Factory-Spec Fitment - Designed to match Yamaha tolerances for proper alignment and installation.. Durable Internal Components - Heavy-duty gears and bearings support long-term reliability.. Complete Assembly Unit - Pre-assembled design reduces install time and simplifies replacement.. Engine & Boat Compatibilit