The clutch is a component in a vehicle that sits between the engine and gearbox. Its primary function is to transmit or prevent transmission of drive from the engine to the gearbox. The clutch connects two rotating shafts, and there can be two or more of these under the hood. The clutch has several components that are key to its operation, including the pressure plate, friction plate, and thrust bearing. The pressure plate applies a clamping force (pressure) which holds the driven friction disc between it and the flywheel. The friction plate sits between the engine flywheel and the clutch pressure plate. The thrust bearing provides a medium of actuation between the rotating clutch assembly and the static clutch fork and transmission.

The clutch has three main jobs:

• To engage drive to the vehicle gearbox
• To disengage drive to the vehicle gearbox
• To allow smooth standing starts through clutch control which partially engages allowing the clutch to slip.

When the clutch pedal is pressed, a cable or hydraulic piston pushes on the release fork, which presses the throw-out bearing against the middle of the diaphragm spring. With the spring pushed, the clutch disc is then disconnected from the rotating flywheel that is attached to the engine. When the pedal is released, the disc will engage contact with the flywheel and transmit the torque from the engine to the rest of the drivetrain. Clutches require a mode of actuation in order to break the transmission of torque, and the clutch pedal is a method of leverage to disengage drive from the engine to transmission from within the vehicle.