Multiquip EM20407 Gearbox Assembly

The Multiquip EM20407 Gearbox Assembly is a genuine OEM component designed for a wide range of Multiquip and Whiteman walk-behind power trowel models, including the J36, B46, BH90C, BS90C, JH90C, PRO36, PRO46, JS36H90, HPHA36C5H, and related series machines. As a factory-original part, the part is built to the exact specifications of the gearbox it replaces, ensuring correct torque transmission and blade-speed performance. DHS Equipment supplies this part direct, so you can verify fitment by model code and order with confidence. Confirm your trowel's model number against the fitment list before ordering to ensure compatibility.

Key Features

• Factory-Original Construction — Manufactured to OEM specification for precise gear mesh, correct reduction ratio, and consistent blade-speed output on Multiquip and Whiteman walk-behind trowels.
• Drop-In Replacement — Engineered to match the original mounting bolt pattern and shaft dimensions, so the part installs in the same position as the factory unit without modification.
• Broad Trowel Series Coverage — Fits J36, JA, B46, BA, BH, BS, JS, PRO, CA, M30, and HPHA/HPLA series walk-behind power trowels across Multiquip and Whiteman product lines.
• Sustained Power Transfer — A properly functioning gearbox keeps blade rotation smooth and consistent; a worn or seized unit causes uneven finishing, blade flutter, and potential drivetrain damage.
• Genuine OEM Traceability — Sourced directly through Multiquip's OEM supply chain, so part number this part matches the original engineering drawing and service manual specification.

The gearbox assembly on a walk-behind power trowel is the core mechanical link between the engine and the finishing blades. It reduces engine speed to the correct blade-rotation speed and transmits torque evenly across the blade spider, which is what allows the trowel to produce a flat, burnished concrete surface. When the gearbox wears out — through oil starvation, bearing failure, or gear deterioration — the blades lose consistent speed and the machine can no longer produce an even finish, often leaving chatter marks or requiring the operator to make multiple additional passes. Replacing the gearbox assembly with the correct OEM unit restores full mechanical integrity to the drivetrain.

Part Details

Compatibility & Fitment

Verify Before You Order

Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.

Why Buy From DHS Equipment

Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.

Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.