What are the symptoms of a slipping clutch disc?

[McClayton]

When the clutch disc slips, the following symptoms will occur: the car cannot start or has difficulty starting; the engine's power cannot be fully transmitted to the drive wheels, resulting in weak driving performance; in severe cases, a burning smell caused by overheating of the friction lining may be emitted. Below is relevant information about clutch disc slipping: 1. Causes of slipping: The clutch pedal free travel is too small or non-existent, causing the release bearing to frequently press against the diaphragm spring, keeping the pressure plate in a semi-engaged state; reduced elasticity of the diaphragm spring; excessive wear or hardening of the friction disc surface, oil contamination, or exposed rivets. 2. Precautions: Insufficient pressure between the clutch disc and the driven plate or inner/outer pressure plates, causing the clutch disc to not be tightly pressed and leading to slipping. If the clearance adjustment is improper, check whether the surfaces of the intermediate pressure plate and the thrust plate are flat and undamaged. Generally, their contact surface should reach over 80% to ensure normal contact between the two clutch discs and prevent slipping during operation.