The drive wheel on a clutch-drive support assembly was slightly loose and caused clutch failures in service after 680,000 cycles. After failure, removal of the taper pin holding the drive wheel on the shaft was difficult, indicating that the pin was tight in the assembly. The taper pin was made of 1141 steel, the shaft 1117 steel, and the drive wheel 52100 steel. It was found that failure of the clutch-drive support assembly occurred as a result of fatigue fracture of the taper pin. A loose fit between the drive wheel and the shaft and between the drive wheel...