A vehicle's powertrain, also called the powerplant, consists of those parts or components that conduct the vehicle's power from the original source of energy to the surface of the road. In most modern vehicles, the powertrain includes the engine, transmission, drive shaft, differentials and what is known as the final drive.
Powertrains do not just apply to conventional road vehicles. Boats, airplanes, tanks and tractors also possess them, though the end components — the final drives — are commonly different from normal cars or trucks. For example, tanks and tractors may include drive wheels and continuous tracks as part of their powertrains, whereas boats and planes often boast propellers. In automotive terms, the powertrain (also frequently called the "running gear" in this context), combined with the frame of the vehicle, forms the chassis. When the engine and transmission are removed from the powertrain, the remainder is what the automotive industry commonly refers to as the driveline or drivetrain. Many automotive manufacturers offer what they term powertrain warranties, amenities that insure the functioning of related parts or their replacement in cases of wear or breakage. Powertrain warranties typically extend up to a specified mileage limit, after which they are voided. Furthermore, such warranties commonly exclude coverage of parts that are considered "wear parts," or parts that are expected to demand replacement in more frequent intervals. Wear parts often include such items as clutches, CV joints and boots, to name a few.