Imer Workman 350 Gearbox

Features

• Replacement gear box for workman 350 mixers

The Imer Workman 350 Gearbox is the heavy‑duty, belt‑driven transmission at the heart of the IMER Workman II 350 towable mixer, engineered to deliver the torque, quiet operation, and long service life needed to mix 9.5 cu ft batches of concrete, mortar, and stucco on demanding jobsites. Sold as a complete OEM assembly under part number 3210476, the Imer Workman 350 Gearbox is the correct replacement gear box for restoring drum drive performance when the original unit is worn, noisy, or damaged.

What is the Imer Workman 350 Gearbox?

Retailers describe this component as:

• “3210476 Imer Workman 350 Gearbox” – Contractors Direct.

• “Imer Workman 350 Gearbox” – Blades Direct.

• “Repair Part 3210476 Imer USA Gearbox for Workman 350” – IMERParts.com.

It is a complete belt‑driven mixer gearbox that mounts inside the Workman 350 mixer arm and transfers power from the electric motor or gas engine to the mixing drum via a V‑belt and internal reduction gears.

Key identifiers:

• IMER OEM part number: 3210476.

• Application: Imer Workman 350 / Workman II 350 towable multimixers (gas and electric models).

• Function: Main drum‑drive gearbox (not the dump gear; dumping is handled separately by the worm‑drive dump gear system).

Role of the Gearbox in the Workman 350 Mixer

The Workman 350 is described by IMER as a belt‑driven gearbox mixer with a worm drive dump gear, replacing older crown‑gear designs. In this setup:

• The engine or electric motor turns a pulley.

• A V‑belt transmits power to a pulley on the gearbox input shaft inside the mixer arm.

• The Workman 350 Gearbox reduces speed and increases torque, driving the drum shaft and paddles at the ideal mixing speed.

This offers several advantages:

• Quiet operation – belt and enclosed gearbox drive is much quieter than exposed crown gears.

• Greater durability and lower maintenance – no huge open crown gear to lubricate or replace.

• Fast, efficient mixing – IMER’s video notes the “gear box driven IMER WORKMAN 350 II blends material 2x to 3x faster than its competitors.”

The 3210476 gearbox is the central power transmission component that makes this performance possible.

OEM Quality and Construction

IMERParts describes the 3210476 Workman 350 Gearbox as follows:

• “With its durable construction and precise engineering, this gearbox is designed to deliver reliable performance and long‑lasting durability.”

• “It provides smooth and efficient power transmission, ensuring your Workman 350 mixer operates at peak efficiency.”

• “This IMER gearbox is built to withstand the tough demands of construction sites and high‑volume mixing tasks.”

Key construction features:

• Heavy‑duty, sealed gearbox housing.

• Internal reduction gearing sized for 12 cu ft drum / 9.5 cu ft batch output loads.

• Mounting flanges and bolt pattern to fit directly into the Workman 350 mixer arm.

Using the OEM 3210476 gearbox ensures compatibility with IMER’s specified belt sizes, pulleys, and mounting hardware.

Workman 350 Mixer Specs and How the Gearbox Fits In

To understand the Imer Workman 350 Gearbox, it helps to look at the Workman 350 mixer as a whole:

• Drum capacity: 12 cu ft; Batch output: 9.5 cu ft.

• Power options: 5.5 HP Honda GX gas engine or 1.5 HP 110/220V single‑phase electric motor.

• Drum drive system: One‑piece removable drum, belt‑driven gearbox, aggressive paddles.

• Dump gear: Worm‑drive dump gear for easy tilting, separate from the main gearbox.

The gearbox has to convert motor speed and torque into reliable drum rotation for:

• Concrete, mortar, and stucco mixes.

• Heavy aggregates and full 9.5 cu ft batches.

• Continuous duty on commercial job sites.

The 3210476 gearbox is designed specifically around these load and duty requirements, so substituting non‑OEM transmissions is not recommended.

Gearbox vs Tilting Drum Gearbox / Dump Gear

It’s important to distinguish the Workman 350 drum‑drive gearbox from other gear components in IMER’s product line:

• 3210476 Imer Workman 350 Gearbox:

  • Drives the drum rotation via belt and internal gears.

  • Used for mixing; mounted inside the mixer arm.

• 3209786 Imer Tilting Drum Gearbox:

  • A separate tilting drum gearbox used on some tilting drum mixers for controlled dump via worm screw.

  • Not the same as the Workman 350 mixing gearbox, though similar worm‑drive concepts appear in the Workman dump gear.

IMER USA Direct’s “Workman 350 Gearbox Part” collection includes:

• IMER Workman 350 Dump Gear Box Complete.

• IMER Workman 350 Gearbox Case Half.

• IMER Workman 350 Mixer Bearing, and other related parts.

For drum rotation, 3210476 is the correct complete gearbox assembly.

Common Symptoms of a Failing Workman 350 Gearbox

You may need to replace the Imer Workman 350 Gearbox when you notice:

• Grinding or knocking noises from the mixer arm, especially under load.

• Drum stalls or struggles even though the motor or engine appears to run properly.

• Oil leaks from the gearbox housing or visible cracks/damage.

• Excessive backlash or play in the drum drive, causing jerky mixing.

The Workman 350 parts manual also notes that the gearbox mounting nuts inside the arm can be loosened to adjust belt tension, and that this maintenance should be done regularly. If belt tension is correct and the drum still slips or the gearbox is noisy, internal gearbox wear may be the cause.

Because the gearbox is factory‑sealed and complex, most users replace the entire 3210476 gearbox rather than attempting internal repairs.

Gearbox Adjustment and Related Parts

The Workman 350 parts PDF notes:

• “To tighten the belt inside the arm, loosen the 4 nuts which anchor the gearbox on the arm.”

• For Workman 350 II, certain torque values (e.g., 300 ± 20 Nm) are recommended for structural components.

This means the gearbox is mounted in a way that allows some movement for belt adjustment. Related key parts in the Workman 350 Gear Box Parts subassembly include:

• 20964MER – H2 Shaft.

• 21163MER – Pinion.

• 4885MER – Bearing.

• Various keys, circlips, seals, and case halves.

IMER USA Direct breaks out these parts in its Workman 350 Gearbox Part collection, so you can buy case halves, bearings, and shafts individually, or the complete 3210476 gearbox as a unit.

Pricing and Availability

The Imer Workman 350 Gearbox is a major component and is priced accordingly:

• Contractors Direct lists “3210476 Imer Workman 350 Gearbox” at $897.13 USD (contractor price; availability may vary).

• Blades Direct offers “Imer Workman 350 Gearbox – SKU 3210476” with a similar price bracket and about $25.95 delivery in example listings.

• HandGearPro promotes it as “Imer Workman 350 Gearbox – Sale! $826.59 $150.00”, indicating promotional pricing in some markets.

• IMERParts.com lists “Repair Part 3210476 Imer USA Gearbox for Workman 350”, with a typical 1‑year warranty and 30‑day returns.

Because the gearbox is central to mixer operation, most IMER dealers keep at least a few units in stock or can order them quickly from IMER USA.

When to Replace vs Repair

You might opt for a full gearbox replacement when:

• Internal gears or bearings are significantly worn or damaged.

• The gearbox housing is cracked or leaking and case halves are expensive individually.

• You want to minimize downtime, since a complete OEM gearbox is faster to swap than a full rebuild.

You might consider partial repairs (bearings, seals, case halves) when:

• Damage is clearly localized (e.g., a leaking seal, worn bearing).

• You have technical expertise and time to disassemble and rebuild.

• The cost availability of internal parts makes repair economical.

IMER’s parts breakdown for Workman 350G II “Gear Box Parts” clearly lists each internal component, giving advanced users the option to rebuild rather than replace. However, for many contractors, the 3210476 Workman 350 Gearbox is the most straightforward solution.

Why Choose the OEM Imer Workman 350 Gearbox

Using the OEM Imer Workman 350 Gearbox (3210476) instead of an improvised or non‑OEM solution ensures:

• Direct bolt‑in fit with existing mounting holes, pulleys, belts, and drum shafts.

• Correct reduction ratio and torque output for the Workman 350’s 12 cu ft drum and 9.5 cu ft batch rating.

• Known compatibility with gas and electric power options (5.5 HP Honda GX, 1.5 HP electric motor).

• Factory support and warranty from IMER USA and its authorized distributors.