Multiquip 1851 Worm Gear B Input Shaft

The Multiquip 1851 Worm Gear B Input Shaft is a genuine OEM component designed for Multiquip and Whiteman walk-behind power trowel series including J36, B46, CA4HC, BS46, JH90C, and related models. As a direct OEM replacement, part 1851 is manufactured to the same specifications as the original, ensuring correct mesh engagement within the gearbox assembly. This part is compatible across a broad range of Whiteman and Multiquip walk-behind trowel families, making it a go-to replacement for contractors maintaining multiple machines on the job. Verify your model code against the fitment list before ordering to confirm compatibility.

Key Features

• Genuine OEM Gear Geometry — Machined to original tooth profile and pitch specifications, ensuring proper worm-to-gear mesh and torque transfer within the trowel gearbox.
• Drop-In Shaft Replacement — Engineered to match the original input shaft dimensions, allowing direct installation without custom fitting or machining.
• Broad Trowel Family Coverage — Fits J36, JA, B46, BA, C, CA, and HDA series Whiteman and Multiquip walk-behind power trowels, including BH11C, JH90C, BS46, CA4HC, PRO36, PRO46, and more.
• Smooth Blade Speed Control — A correctly functioning worm gear input shaft maintains consistent rotational input to the trowel blade assembly, supporting even finishing passes across concrete surfaces.
• Protects Downstream Gearbox Components — Worn or damaged input shaft gearing accelerates wear on mating components; replacing part 1851 at first sign of wear limits secondary damage to the gearbox.

The worm gear input shaft is a core element of the trowel's gearbox, transferring rotational power from the engine through the gear train to drive the finishing blades. The worm gear design allows the system to reduce speed and increase torque while changing the axis of rotation, enabling precise blade pitch and speed control. When this shaft wears or loses tooth integrity, the result is slipping, noisy operation, or complete loss of blade drive — all of which bring finishing work to a halt.

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.