Transmission and Drivetrain Parts for Heavy Equipment: Gearboxes, Torque Converters, Clutch Kits, and More

Why Equipment Operators and Fleet Managers Trust Imara Engineering

Sourcing the wrong transmission part is not just costly, it is a risk to your machine, your timeline, and your bottom line. The difference between a reliable supplier and a generic parts dealer comes down to three things: technical accuracy, part quality, and the speed at which they can get the component to your site.

At Imara Engineering, our approach to every order is built on the following:

1. Fitment confirmed before despatch. We cross-reference your machine model, serial number, and application against manufacturer specifications. You do not receive a part and then discover it is the wrong configuration.
2. OEM-grade quality on every component. Our aftermarket parts are manufactured to the same dimensions, metallurgical, and tolerance standards as genuine components. We do not stock budget-grade substitutes.
3. Honest aftermarket guidance. For wear items such as clutch plates, bearings, and seals, high-quality aftermarket components routinely match OEM service life. Where genuine parts are the better call, we will tell you directly.
4. Worldwide logistics capability. We ship heavy equipment drivetrain parts to Australia, the USA, Canada, and across international markets, with freight options scaled to your urgency.
5. A catalogue built around real machines. Our range is not built from a general parts database. It reflects the Caterpillar, Komatsu, Allison, and ZF platforms that are running on job sites right now.

Our Complete Transmission and Drivetrain Range

The categories below cover the full drivetrain assembly from the input shaft to the final drive. Each section links to a dedicated collection stocked with the components your machine needs.

Transmissions & Gearboxes

The transmission governs how engine torque is converted and transferred to your machine's drive system. Our Transmissions & Gearboxes range covers complete assemblies and remanufactured units across manual, automatic, and hydrostatic configurations, including Komatsu Torqflow transmissions, Caterpillar Powershift units, ZF industrial gearboxes, and Clark assemblies used in forklifts and loaders. This hub collection links through to three specialist child pages:

• Transmission Assemblies: model-specific CAT powershift and CX series units
• Manual Transmissions: manual gearbox replacements for dozers, excavators, and loaders
• Automatic Transmissions: Allison and Caterpillar automatic units with full assembly compatibility

Torque Converters

The torque converter is the fluid coupling between your engine and transmission, and when it begins to slip, overheat, or fail to stall correctly, power transfer efficiency drops across the entire drivetrain. Our torque converter range covers Caterpillar, Komatsu, and Allison applications, including units for CAT D8 dozers, excavators, and wheel loaders. All units are built to OEM impeller, turbine, and stator geometry specifications for full performance restoration.

Automatic Transmission Components

Machines running Allison, Caterpillar, or ZF automatic transmissions rely on precise hydraulic pressure control to shift correctly. When that control breaks down, the fault often lies in two specific component groups housed within this category:

• Valve Bodies: Allison 1000 series, ZF 6HP26, and 8HP variants that regulate shift logic and hydraulic pressure
• Transmission Solenoids: shift and pressure control solenoids for Allison, Caterpillar, and Komatsu platforms

Transmission Components

When a full assembly swap is not required, targeted internal repairs are the most efficient path back to productivity. Our Transmission Components hub gives you access to every major internal part category:

• Gears & Shafts: input, output, layshaft, and drive gear replacements
• Bearings & Seals: full bearing and seal coverage for all transmission positions
• Synchronisers: synchro rings, hubs, and sleeves for manual gearbox applications
• Shift Components: shift forks, rails, levers, and drums
• Transmission Rebuild Kits: complete overhaul kits for Allison, Caterpillar, and Komatsu transmissions

Clutch Parts

From bulldozers to excavators, the clutch assembly is a high-wear system that demands accurate replacement parts. Our Clutch Parts is divided into four dedicated collections to help you find exactly what your repair requires:

• Clutch Kits: complete assembly kits for full clutch replacements
• Clutch Plates: friction discs and drive plates in sintered and organic materials
• Pressure Plates: heavy-duty units for Caterpillar and Komatsu applications
• Release Bearings: hydraulic and mechanical release bearing replacements

Differential Parts

The differential transfers drive torque to your machine's axles, and damage at this stage of the drivetrain often results in severe traction loss or uneven drive behaviour. Our differential parts range covers assemblies, ring and pinion gear sets, differential bearings, and seal kits for CAT, Komatsu, and Dana platforms across dozers, loaders, and articulated trucks.

Machine Compatibility: Platforms and Models We Cover

Our transmission and drivetrain parts for heavy equipment are matched to the following OEM platforms as a core range:

Caterpillar (CAT)

• Dozers: D6, D8, D8T, D9, D10, D10N
• Motor Graders: 140G, 140H
• Articulated and Rigid Trucks: 725, 745, 777D
• Track Loaders: 953, 963
• Backhoe Loaders: 416

Komatsu

• Wheel Loaders: WA180 and WA series
• Dozers: D20P and series variants
• Excavators: PC series

Allison: 1000 series heavy-duty automatic transmissions across trucks and off-highway equipment

ZF: 4HP20, 4HP22, 6HP26, and 8HP series transmissions used in Liebherr, Volvo Construction, and mining equipment

Clark: Industrial and construction equipment transmissions

If your machine is not listed here, contact Imara Engineering with your model, year, and serial number. We will confirm availability or source the component directly.

A Note on OEM Versus Aftermarket for Drivetrain Components

The OEM versus aftermarket question is one we answer honestly. Dealership-supplied OEM parts carry a significant price premium, and for a large number of drivetrain repair applications, that premium does not deliver a measurable difference in field performance or service life.

The aftermarket components Imara Engineering stocks are manufactured to the same specifications as genuine parts, with full dimensional and material compliance. For high-wear items such as clutch friction plates, transmission bearings, seals, and solenoids, quality aftermarket components are a proven and widely accepted industry standard.

There are applications where OEM fitment is the more appropriate choice, particularly for complex assemblies under active manufacturer warranties or in specialist operating environments. In those cases, we will tell you clearly. Our recommendation is always based on what is right for your machine and your operating conditions, not on margin.