This friction disc set transmits torque through the clutch pack when the driver engages the clutch pedal or electro-hydraulic control. The discs sit between the pressure plate and the flywheel, alternately splined to the input shaft and the clutch housing. When the pack is compressed, the friction surfaces lock the discs together, transferring engine power to the transmission input. Worn friction material reduces clamp force, causing slip under load and heat buildup that can warp the pressure plate. The manufacturer machines these discs to the same thickness and surface finish as the original assembly, so the clutch-pack stack height and engagement timing remain within specification. On reinstallation, inspect the flywheel surface for scoring and replace the pilot bearing if worn.