Yamaha - Gear, Drive Lower Unit Drive Gear 6D8-11536-00-00. Overview. Anytime you're working on a Yamaha lower unit, the drive gear is one of those parts you don't cut corners on. It's what takes the engine's rotation and puts it to work, so when it's worn, you feel it right away. I've seen setups go from rough and noisy to smooth just by replacing a tired drive gear. When everything meshes right, the whole motor just runs cleaner and more predictable out on the water.. Key Features. • Primary Drive Function - Transfers engine rotation through the lower unit for consistent propulsion.• Precision-Cut Gear Teeth - Ensures smooth meshing with mating gears to reduce noise and vibration.• High-Strength Construction - Built to handle continuous torque and load without premature failure.• Exact Fit Engineering - Matches Yamaha specifications for proper alignment and dependable operation.• Corrosion-Resistant Finish - Helps protect against wear and marine exposure inside the lower unit.. Engin