While clutch designs vary for light, medium, or heavy-duty applications, the primary purpose of the clutch is to transfer torque from the engine to the transmission. It does this by interrupting or "interrupting" the flow of power between the engine and transmission when the vehicle is stopped (engine running) so that you can change gears.

    The important components of the heavy duty truck clutch mainly have 4 parts: flywheel, clutch cover, clutch plate, and pressure plate.


    The flywheel stores rotational energy from the engine acts as driving friction for the clutch disc and provides a ring gear for the starter motor to engage. It is bolted to the engine crankshaft and clutch cover assembly.

    Clutch cover assembly

    The clutch cover assembly applies the required design plate load pressure to fully engage the clutch plate and pressure plate and provide torque power to the transmission. The cover assembly prevents these components from slipping when the clutch is engaged.

    Clutch disc

    The clutch disc is splined to connect power from the engine to the transmission. The clutch disc contains a damper that absorbs engine vibration, gear rattle, noise, and uneven driveline power pulses.

    The clutch disc is located between the flywheel and the pressure plate. The clutch disc has a bumper plate (made of riveted friction material, such as brake linings) that connects the engine to the transmission. When the clutch is engaged (when your foot takes your foot off the pedal), the clutch cover assembly compresses the clutch plate and pressure plate, making a firm connection with the flywheel and engine.

    Pressure plate

    As an integral part of the cap assembly, the platen acts as a contact surface between the disc and cap assembly. When the driver depresses the clutch pedal, the pressure plate is activated to release the clutch. The pressure plate will then move away from the flywheel. This "releases" the clutch plates from the pressure plate and flywheel.