This rubber coupling transmits torque from the engine to the power take-off drive on the host combine. It sits between the engine output and the input shaft of the driven implement, absorbing torsional vibration and shock loads during engagement and operation. A failed coupling shows as excessive driveline vibration or a sudden loss of drive to the implement. The coupling is manufactured to the original stiffness and hole pattern, which keeps the driveline balanced and prevents premature wear on the adjacent universal joints. On replacement, ensure the mating flanges are clean and the fasteners are torqued to specification.