(of a motor vehicle) group of components that deliver power to the driving wheels;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 drivetrain of a motor vehicle is the group of parts that deliver power to the wheels that move the vehicle.[1] The drivetrain includes the transmission or transaxle, driveshafts, differentials, axles and wheels.[2] It does not include the engine or motor that creates the power.[2] In contrast, the powertrain includes the engine and the drivetrain. In order to transmit power from the engine to the rear wheels, the drivetrain uses some of that power to work.[3] Drivetrain loss is the power lost, measured in horsepower, between what the engine generates and what is available at the wheels.[4] As power is transmitted through the drivetrain, forces including inertia, drag and friction cause some power to be wasted.[4] The more component parts power is transmitted through, the more power is lost. However each combination of drivetrain parts is different as to how much is lost.[4] The automatic transmission wastes the most power of any drivetrain component.[3]

Vehicle drivetrain (excluding #1, the engine)


  1. "Drivetrain". Automotive Handbook (3rd ed.). Bosch. 1993. p. 536. ISBN 0-8376-0330-7.
  2. 2.0 2.1 "What is a Drivetrain?". Mister Transmission (International) Limited. Retrieved 30 August 2015.
  3. 3.0 3.1 Jeff Smith (1 November 2003). "Drivetrain Power Loss - The Brutal Truth". Hot Rod Network/TEN. Retrieved 30 August 2015.
  4. 4.0 4.1 4.2 David Pratte (7 May 2010). "Drivetrain Power Loss - The 15% "Rule"". Super Street Online/TEN. Retrieved 30 August 2015.