Automotive Clutch 101 – How does your clutch work
The clutch disk is in between the pressure plate and the flywheel. A clutch disk is held against the flywheel under pressure from the pressure plate. Because the engine is running and the clutch is engaged (i.e., clutch pedal up), the flywheel spins the clutch plate and the transmission. When the clutch pedal is depressed, the throw out bearing is activated. This causes the pressure plate to stop applying pressure to the clutch disk. Because of this the clutch plate stop receiving power from the engine. So now gears can be shifted without damaging the transmission. When the clutch pedal is released, the throw out bearing is deactivated. The clutch disk is again held against the flywheel, allowing it to start receiving power from the engine.