The transmission of a heavy goods vehicle (HGV) is a mechanical system that transmits the power from the engine to the drive wheels. It is responsible for controlling the speed and torque of the vehicle, allowing it to move at different speeds and on different types of terrain. There are two main types of transmissions used in HGVs: manual and automatic. A manual transmission, also known as a stick shift, requires the driver to manually shift gears using a gear lever and a clutch pedal. An automatic transmission, on the other hand, uses a system of gears and a torque converter to automatically shift gears, eliminating the need for the driver to manually shift gears. The transmission of a HGV includes gears, bearings, and other mechanical components that are subject to wear and tear due to the forces and weight of the vehicle. The transmission oil needs to be checked and changed regularly, as recommended by the vehicle manufacturer. A transmission that is not properly maintained can cause problems such as difficulty shifting gears, slipping gears, or a lack of power. It's worth mentioning that the transmission plays a critical role in the performance and efficiency of the vehicle, as well as its safety. A properly functioning transmission is essential to the smooth operation of the vehicle, and the driver's ability to control the speed and direction of the vehicle.