Yamaha Lower Unit Assembly - 6J8-45300-E2-4DYamaha Lower Unit Assembly Complete Drivetrain 6J8 45300 E2 4D Overview The Yamaha Lower Unit Assembly 6J8 45300 E2 4D is what takes all that engine power and actually puts it to work in the water. When a lower unit starts going bad, youll notice it quicknoise, vibration, or just not getting the push you expect. Ive seen plenty of guys chase individual issues inside, but sometimes its smarter to swap the whole unit and be done with it. This is the