Yamaha - Lower Unit Assembly Gearcase Component 6CB-45300-03-NA. Overview. When a lower unit starts going, you don't have to guess-you'll feel it every time you throttle up. This assembly is what turns engine power into clean, dependable movement in the water, and when it's right, the boat just feels solid. I've swapped plenty of these on SHO motors, and a fresh unit makes a big difference in how smooth and quiet everything runs. If your current one's showing wear, this is the kind of replacement that brings confidence back to your setup.. Key Features. • Smooth Power Transfer - Delivers consistent propulsion from engine to propeller.. • Precision Gear Alignment - Ensures clean engagement and reduces internal wear.. • OEM Fit Accuracy - Matches Yamaha factory specs for proper installation and performance.. • Corrosion Resistant Build - Designed to handle harsh saltwater and freshwater environments.. Engine & Boat Compatibility. • VF200LA 2009-2020• VF250LA 2009-2020. Superseded by: 6CB