Caterpillar Transmission Assemblies: CX31, CX38, D8, D9 and Powershift Units for Heavy Equipment
Caterpillar transmission assemblies are among the most structurally complex components in the heavy equipment drivetrain, engineered to transfer full engine torque through continuous high-load cycles on dozers, graders, haul trucks, and loaders. Imara Engineering supplies direct-replacement CAT transmission assemblies covering the CX31, CX38, and TA22 powershift series, plus model-specific units for the D6, D8, D8T, D9, and D10 platforms, sitting within our Transmissions & Gearboxes collection inside the broader Transmission & Drivetrain catalogue.
Every unit is built or remanufactured to Caterpillar's original engineering specifications, with build variant confirmed against your machine serial number before dispatch, eliminating the risk of receiving a dimensionally similar unit that requires modification to install. Remanufactured and rebuilt Caterpillar transmissions in our range are a proven and widely accepted alternative to new OEM assemblies, particularly where dealership lead times are not workable for your job schedule. Imara Engineering ships CAT transmission assemblies worldwide with stocked units dispatched promptly and expedited freight available for machines that cannot afford to wait.
Collection:
Caterpillar Transmission Assemblies
Understanding the CAT Powershift Transmission Before You Order
Caterpillar's powershift transmission design uses a series of hydraulically actuated clutch packs, a torque converter, and a planetary gear arrangement to shift gears under full engine load without interrupting drive torque. This is what makes the powershift system suited to the continuous load-and-push cycles of dozers, graders, and haul trucks. The machine never loses momentum through a gear change.
The three primary powershift variants in our range each serve a distinct application profile:
- CX31 and CX31 Automatic Transmission: A medium-duty six-speed powershift assembly used across CAT track-type tractors, motor graders, and certain articulated trucks. The Cat CX31 automatic transmission is one of the most commonly replaced assemblies across the CAT mid-range equipment fleet.
- CX38 Transmission: A heavier-duty variant of the CX series, used on larger CAT equipment platforms with higher torque output requirements.
- TA22 Transmission: Fitted to specific CAT wheeled and tracked platforms, the TA22 is a torque converter-driven powershift unit available as a direct-replacement assembly and as a cat ta22 transmission for sale through our stock programme.
- 3208 CAT Transmission: The 3208 CAT transmission and 3208 CAT automatic transmission are engine-integrated automatic units found in older CAT equipment and certain marine and industrial applications. Legacy units are available through our sourcing network.
CAT Transmission Assemblies by Model and Application
Our coverage is organised by machine platform to help you confirm the correct assembly for your equipment.
CAT Dozer Transmissions
CAT dozer transmissions represent the highest-demand segment of our assembly range. Units are stocked or sourced across the following platforms:
- CAT D6 transmission for mid-range track-type tractors in construction and forestry
- CAT D8 transmission and CAT D8T transmission for sale: high-tonnage earthmoving and land clearing dozers
- CAT D8 dozer transmission remanufactured units: available where new assemblies carry extended lead times
- CAT D9 transmission for large-scale earthmoving and mining site preparation
- CAT D10 transmission for the highest-capacity CAT dozer platform in active production
All dozer transmission assemblies are cross-referenced against machine serial number ranges to confirm that the unit supplied matches the specific build configuration fitted at the factory.
CAT Grader and Haul Truck Transmissions
- CAT 140H transmission for sale: a direct-replacement powershift unit for one of CAT's most widely deployed motor graders
- CAT 725 transmission for articulated haul trucks in medium earthmoving and quarry applications
- CAT 963 transmission for track loaders operating in demolition, construction, and stockpile management
CAT Loader, Skidder, and Specialised Equipment Transmissions
- CAT 416 transmission for backhoe loaders used across civil construction and utility maintenance
- 518 CAT skidder transmission for forestry applications requiring high-torque, low-speed drive
- CAT forklift transmission assemblies for material handling and warehouse logistics equipment
New, Rebuilt or Remanufactured: Choosing the Right Option for Your CAT Transmission
When a CAT powershift transmission reaches the end of its service life, operators typically have three sourcing options. The right choice depends on machine age, budget, lead time, and the operating environment:
New OEM Assembly: The highest-cost option, sourced directly through the Caterpillar dealer network. Appropriate for machines under active warranty or operating in conditions where full OEM traceability is contractually required.
Remanufactured Caterpillar Transmissions Remanufactured Caterpillar transmissions are factory-standard assemblies stripped to base components, inspected against OEM tolerances, rebuilt with new wear parts, and tested prior to dispatch. They carry warranty coverage and are dimensionally and functionally equivalent to new units. For most repair applications, remanufactured units are the most cost-effective path to a full-performance restoration.
Rebuilt Caterpillar Transmissions Rebuilt Caterpillar transmissions are workshop-restored assemblies built to OEM specification using a combination of new and serviceable reconditioned components. They are a proven option for legacy models where remanufactured stock is limited, and new units are no longer in active production.
At Imara Engineering, we stock both remanufactured and rebuilt units alongside new assemblies where available, and our technical team will recommend the appropriate option based on your machine's age, condition, and operational requirements.
How to Identify Your Caterpillar Transmission Before Ordering
Ordering a replacement Caterpillar Powershift transmission requires more than a model name. Use the following to ensure your order is accurate:
- Machine Model Number: Located on the cab door or frame plate. For example: D8T, 140H, 725.
- Machine Serial Number: Found on the identification plate on the machine frame. Serial number ranges determine which transmission variant was fitted at manufacture.
- Transmission Part Number: Stamped directly on the transmission housing. This is the most reliable identifier for confirming the exact assembly specification.
- Configuration Details: Automatic or manual shift configuration, number of speeds, and torque converter type, if known.
If you have the model and serial number but cannot locate the transmission part number, contact Imara Engineering directly, and our technical team will identify the correct unit from the information available.
Frequently Asked Questions
The CX31 is a medium-duty powershift unit used across CAT mid-range equipment. The CX38 is a heavier-duty variant built for platforms with higher torque output requirements. Serial number verification determines which applies to your machine.
Yes. Remanufactured units in our range carry warranty coverage and are rebuilt to OEM tolerances. Our team will provide warranty terms specific to the unit you are ordering.
In most cases, yes. We carry coverage for legacy CAT platforms, including the 3208 series and older D-series dozers. Contact us with your serial number, and we will confirm availability from our supply network.
Stocked units are dispatched promptly with full freight packaging. International lead times depend on destination and freight class. Contact us at the time of order, and we will provide a confirmed dispatch and delivery window.
Not always, but it is strongly recommended if the torque converter has not been replaced recently. Fitting a new transmission against a worn torque converter can accelerate wear on the new assembly. Our Torque Converters range carries the complementary CAT units for machines requiring both components.

