Yamaha Lower Unit Assembly - 6M8-G5300-10-4DYamaha Lower Unit Assembly Outboard Drivetrain 6M8 G5300 10 4D Overview You can usually tell when a lower unit is on its way outthings get noisy, shifting feels off, and the motor just doesnt run as clean. Swapping in a fresh Yamaha assembly like this brings everything back to how it should feel on the water. It bolts up right, runs smooth, and gives you that solid, predictable performance you expect. Its the kind of part you install once and trust