How does a travel gearbox work?

How does a travel gearbox work?

A travel gearbox, also known as a final drive or track motor gearbox, is an essential component of heavy machinery such as excavators, bulldozers, and crawler cranes. It is responsible for transferring power from the hydraulic motor to the machine’s tracks, allowing it to move forward or backward. In this article, we will explore the inner workings of a travel gearbox and its various components.


The gearbox consists of a set of gears that transmit power from the hydraulic motor to the final drive. These gears include the sun gear, the planetary gears, and the ring gear. The sun gear is connected to the hydraulic motor output shaft and transmits power to the planetary gears. These gears, in turn, are mounted on a carrier and rotate around the sun gear. The ring gear is fixed to the final drive casing and meshes with the planetary gears.


The gears in the gearbox are supported by bearings that ensure smooth and efficient motion. These bearings include the planet carrier bearings, pinion bearings, and final drive bearings. The planet carrier bearings support the planetary gears and carrier, while the pinion bearings support the pinion gear. The final drive bearings support the entire final drive and transmit the force to the machine’s tracks.


The gearbox also contains various seals that prevent oil leaks and contamination. These seals include the input shaft seal, the output shaft seal, and the planetary seal. The input shaft seal prevents oil from leaking out of the gearbox, while the output shaft seal prevents dirt and debris from entering. The planetary seal prevents oil from leaking out of the planetary gears.

Cooling system

Travel gearboxes generate a lot of heat due to the high level of friction and stress they undergo. To prevent overheating, they are equipped with a cooling system consisting of a heat exchanger, pump, and radiator. The pump circulates oil through the heat exchanger, which cools it down before returning it to the gearbox. The radiator dissipates the heat into the environment, keeping the gearbox at a safe operating temperature.

Other components

Other components of a travel gearbox include the housing, which contains all the internal components; the drain and fill plugs, which allow for easy oil changes; and the breather, which equalizes the internal pressure of the gearbox.

travel gearbox image

Installation guide

Before installing a travel gearbox, it is important to ensure that it is compatible with the machine it will be used in. The gearbox should be installed in a clean and dry environment, and all mounting surfaces should be free of debris and damage. The installation process typically involves the following steps:

  1. Position the gearbox onto the mounting surface and secure it in place with bolts or screws.
  2. Connect the hydraulic lines to the input and output ports of the gearbox.
  3. Add oil to the gearbox through the fill plug until it reaches the recommended level.
  4. Start the machine and check for leaks or abnormal noises.

It is important to follow the manufacturer’s instructions and specifications when installing a travel gearbox to ensure optimal performance and longevity.

installation guide image

Applications and use cases

Travel gearboxes are used in a wide range of heavy machinery, including excavators, bulldozers, and crawler cranes. They are typically located at the end of the machine’s drive train and are responsible for propelling the tracks. Without a properly functioning gearbox, these machines would not be able to move efficiently or effectively.

Specific examples of machinery that use travel gearboxes include the Caterpillar D6 bulldozer, the Komatsu PC210 excavator, and the Liebherr LR 1300 crawler crane. These machines are used in construction, mining, and other heavy industries where their durability and high performance are essential.

Maintenance and troubleshooting

To ensure the longevity and optimal performance of a travel gearbox, regular maintenance is required. This includes regular oil changes, inspection of seals and bearings for wear and tear, and monitoring of temperature and pressure levels. Additionally, any abnormal noises or leaks should be addressed immediately to prevent further damage.

If a problem does occur, troubleshooting should begin with a thorough inspection of the gearbox and its components. The most common issues include overheating, leaks, and abnormal noises. In many cases, these issues can be resolved by replacing worn or damaged components or adjusting the oil level and pressure.

Advantages of our travel gearboxes

  1. High efficiency, allowing for maximum power transfer to the tracks.
  2. Robust and durable design, capable of withstanding high levels of stress and wear and tear.
  3. Precision manufacturing, ensuring accurate and reliable performance.
  4. Easy installation and maintenance, minimizing downtime and cost.
  5. Customizable to fit a wide range of machinery and applications.

At our company, we pride ourselves on producing high-quality travel gearboxes that meet the needs of our customers. Our gearboxes are built to last and provide optimal performance in even the most demanding environments. Contact us today to learn more about how our travel gearboxes can enhance the performance of your heavy machinery.

Author: Miya