A throwout bearing is a part of an automotive clutch system that temporarily disengages the engine from the manual transmission while shifting. It translates a linear thrust force from the clutch pedal to the spinning clutch plate assembly mounted to the flywheel. It is a thrust bearing with the inner race attached to the clutch throw out arm and the outer race contacting the clutch de-actuation fingers. It reconciles the disengagement thrust on the spinning clutch assembly with the non-spinning clutch linkage.

• ·      ·      Throwout bearings are pre-lubricated and sealed for life at the factory.
• ·      ·      Replacing a worn-out bearing requires removal of the transmission from the flywheel bell housing to clear the bearing of the input shaft.
• ·      ·      At that point, it is practical to replace the clutch too, since the overall labor is only minimally increased by renewing the entire system.

Mounted on an iron casting called a hub, the bearing slides on a hollow shaft at the front of the transmission housing. The clutch fork and connecting linkage convert the movement of the clutch pedal to the back and forth movement of the clutch throw-out bearing. To disengage the clutch, the release bearing is moved toward the flywheel by the clutch fork. As the bearing contacts the pressure plate's release fingers, it begins to rotate with the pressure plate assembly. The release bearing continues to move forward and pressure on the release levers or fingers causes the force of the pressure plate's spring to move away from the clutch disc. To engage the clutch, the clutch pedal is released and the release bearing moves away from the pressure plate. This action allows the pressure plate's springs to force against the clutch disc, engaging the clutch to the flywheel. Once the clutch is fully engaged, the release bearing is normally stationary and does not rotate with the pressure plate.