Schaeffler Group USA Inc.

Tips for Successful Clutch Diagnostics

• Discuss the symptoms of clutch operation with the customer
• Collect information about clutch operating conditions and working environment
• Road test the vehicle with the customer driving to duplicate the problem
• Establish the vehicle mileage and clutch history and mileage

Failed Clutches with Relative Low Mileage

If the final diagnosis shows signs of driver abuse, take a ride with the customer to observe their driving habits. Explain how certain behavior you observe reduces clutch service life.

Driving Habits and Clutch Wear

Constant engagement and disengagement of the clutch will wear away disc friction material. The wear rate depends largely on the driving habits of the operator and vehicle usage. Driving behaviors and conditions that decrease clutch service life include:

• Riding the Clutch Pedal. Reduces the disc clamping force. Power transfer from the spinning flywheel is not fully applied to the disc, resulting in premature friction material wear. Waiting in traffic with the vehicle in gear and the clutch disengaged loads the release bearing excessively. Over time, this shortens release bearing life and can eventually cause noise.

• High RPM Engagement. Selecting a higher gear causes excessive loading of the disc that can damage the disc hub and torsion springs as well as the clutch drive straps. Over-revving the engine and high-speed downshifting can burst the friction material.

• Excessive Slipping. Slipping the clutch during engagement creates excessive heat, damages the clutch and flywheel contact surfaces and accelerates disc friction material wear.

• Harsh Downshifting

• Lugging the Engine. Occurs when the driver selects the wrong gear for the vehicle speed and load. Under low speed/high load conditions, a lower gear should be used to reduce the torque applied to the clutch.

• Excessive Vehicle Loading

• Engine, Transmission and Suspension Modifications