Mercury – Complete Gearcase | Bravo Three / Three X / Three XR Series | Corrosion-Resistant Alloy | 8M0046735

Overview

When you spend enough time on the water, you learn pretty quickly that your sterndrive’s gearcase is more than just a mechanical part—it’s the heartbeat of the entire propulsion system. When it’s healthy, everything feels right. The boat lifts cleanly onto plane, the shifts come through smooth, and the steering stays predictable even in a tight channel. That’s the kind of confidence the Mercury 8M0046735 Complete Gearcase brings back. It’s built for boaters who need their equipment to show up every single day, whether they’re running a long no-wake zone or pushing a heavy load offshore. There’s a real sense of relief when you know the lower unit under you is brand-new, factory-matched, and ready for whatever your season throws at it.

Key Features

• Complete replacement gearcase for Bravo Three, Three X, and Three XR sterndrives
• Designed for 1.65 gear ratio systems
• XK360 low-copper alloy provides outstanding corrosion defense
• Tri-Paint protective finish creates a durable, long-lasting barrier
• Heavy-duty near-net forged gears ensure strong, smooth engagement
• Engineered specifically to Mercury OEM fitment and performance standards

Engine & Boat Compatibility

Compatible sterndrives:

• MerCruiser Bravo Three (serial No. 0D784124 and up)
• MerCruiser Bravo Three X (0W240000 and up)
• MerCruiser Bravo Three XR (0W240000 and up)
• All models listed must use the 1.65 gear ratio

Ideal for:

• Performance sport boats
• Offshore fishing boats
• Cruisers and heavy cabin boats
• Towing and watersports boats running Bravo platforms
• Twin-engine and high-load Bravo rigs

Performance & Practical Benefits

The 8M0046735 gearcase brings your boat back to that really satisfying “tight and steady” feel you only get from a properly built OEM drive. The forged gears take the load without chatter, so shifts feel solid rather than harsh. Once you’re underway, you’ll notice how smoothly the propellers stay engaged, especially during quick throttle changes or hard turns. It’s the kind of performance difference you can literally feel through the helm.

For boaters who deal with saltwater, repeated haul-outs, or long days at the dock, the corrosion resistance is a major advantage. Mercury’s XK360 alloy and Tri-Paint coating work like armor. You can expect far less pitting, much better long-term protection, and a gearcase that holds up season after season.

Installation is straightforward because this gearcase is built to Mercury’s exact tolerances. No awkward alignment fights, no mismatched surfaces—just a clean fit that restores your Bravo drive to factory standards. It’s the kind of upgrade that immediately improves your confidence in your boat.

Why Buy OEM

If you’re running a Bravo Three, you already understand how much load these drives handle. This isn’t the place to gamble on generic or “universal fit” parts. Mercury OEM gearcases are engineered for the exact torque loads, alignments, and gear mesh these sterndrives demand. They last longer, run smoother, and protect the rest of your drivetrain better than aftermarket alternatives.

Buying OEM also means installation is easier, long-term maintenance stays predictable, and the part performs correctly the first time. It’s the practical, experienced choice—the kind of advice boaters pass along at the ramp or the marina.

FAQ

Q1: Which systems does this gearcase fit?

It fits Bravo Three, Three X, and Three XR sterndrives using the 1.65 gear ratio.

Q2: Why choose OEM instead of aftermarket?

OEM ensures correct fit, stronger gears, better corrosion resistance, and long-term reliability.

Q3: How do I confirm this is the right part?

Match your drive’s serial number and confirm you’re running a 1.65 gear ratio.

Q4: Is this suitable for saltwater?

Absolutely. The alloy and coating are built specifically for harsh marine environments.

Q5: Is installation easy?

Most marine technicians find installation straightforward, and experienced boaters can install it with the right tools.