A clutch disc is a crucial component in a vehicle's manual transmission system. It is a round, flat plate that engages and disengages the engine's power from the transmission when the driver presses the clutch pedal. This allows for smooth gear changes and helps prevent stalling. The clutch disc is typically made of friction material on both sides, which provides the necessary grip to transfer power. Over time, the friction material can wear down, leading to slipping or difficulty in shifting gears. Regular maintenance can help extend the life of the clutch disc and ensure optimal vehicle performance.