Heavy Duty Truck Transmission / Drive trains

 The drivetrain of a motor vehicle is the group of components that deliver power to the driving wheels. This excludes the engine or motor that generates the power. In contrast, the powertrain is considered to include both the engine or motor and the drivetrain.

The function of the drivetrain is to couple the engine that produces the power to the driving wheels that use this mechanical power to rotate the axle. This connection involves physically linking the two components, which may be at opposite ends of the vehicle and so requiring a long propeller shaft or drive shaft. The operating speed of the engine and wheels are also different and must be matched by the correct gear ratio. As the vehicle speed changes, the ideal engine speed must remain approximately constant for efficient operation and so this gearbox ratio must also be changed, either manually, automatically or by an automatic continuous variation.

Heavy–duty commercial truck transmissions offer a wide range of high torque-to-weight ratios and efficient direct drive and overdrive options for better performance and fuel economy. Vocational models match most application conditions, axle ratio specifications and engine specifications.

Most transmissions generally weigh between 100 and 400 pounds (45 to 181 kg), although the type of vehicle can cause this number to be much higher.