LibGuides: Automotive Technology: Drivetrain & Chassis

Definitions

The Chassis is the underpart of a motor vehicle, consisting of the frame on which the body is mounted.

Rolling chassis: When the chassis includes the wheels, engine, transmission, drive shaft, differential, suspension, and the front seats.

A motor vehicle's drivetrain consists of the parts of the powertrain excluding the engine and transmission. The components after the transmission of the drivechain can change depending on if a vehicle is front-wheel, rear-wheel, or four-wheel drive

Main types of Chassis/Frames

The body-on-frame chassis: the body of the vehicle literally sits on top of the frame and work separately from one another. Mainly used in trucks and off-road vehicles.

Unibody chassis: The chassis and body of the vehicle are connected together as one piece and function together as the base of the car. Mainly used in lighter type vehicles like cars.

Types of Drivetrains

Front-Wheel Drive (FWD): Power from the engine goes through a transaxle and travels to the front wheels through an axle shaft allowing the rear wheels to rotate freely.

Rear-Wheel Drive (RWD): Sends power from the engine through a fast-spinning driveshaft to a differential that drives the rear wheels.

Four-Wheel (4WD): Power of engine is applied to all four wheels of a car. This is done by transferring power from the engine to a transmission and then the power is split to both a front and rear axle through driveshafts. Four-Wheel drive can be turned on and off by the vehicle operator.