Yamaha - Lower unit assembly - F100 - 6D9-45300-15-8D - See Description For Applicable ModelYamaha Lower Unit Assembly Gearcase Component F100 6D9 45300 15 8D Overview The Yamaha Lower Unit Assembly 6D9 45300 15 8D is what keeps your engines power translating into smooth, reliable movement on the water. When a lower unit starts to wear or fail, youll feel it immediatelygrinding noise, vibration, or reduced performance. This assembly handles the full transfer of power from the engine to the propeller, so everything depends on it being solid