Yamaha - Lower unit assy - 6BG-45300-12-8DYamaha Lower Unit Assembly Gearcase Component 6BG 45300 12 8D Overview When a lower unit starts going bad, you dont have to guessyoull feel it in vibration, noise, or loss of push in the water. This assembly is what transfers all that engine power into forward motion, and when its dialed in, everything feels smooth and solid. Ive swapped out worn units where the boat instantly handled better and ran quieter. A fresh lower unit like this brings back