Nowadays, the use of CM techniques, especially vibration analysis, is accepted as a principle to investigate defects and fix problems in rotating equipment. Couplings, as one of the important components of rotating equipment, have the task of transferring power from the axis of the driving machine to the driven machine. Defects in couplings caused by misalignment between the driving and moving machine axes and the failure of one of the coupling parts cause increased energy loss, increased vibrations, heating of the bearings and the occurrence of many unforeseen failures. In this research, the troubleshooting of the scraper device of loading unit of Khorasan petrochemical factory is studied that with help of sound measurement and vibration analysis, the condition of the machine is evaluated, the defect and damaged parts are identified and the role of CM is discussed in predicting the remaining working time of the device. Finally, the defect in the device, the failure of the rubber rubber of flexible coupling between the hydrocoupling and the gearbox was diagnosed and the device was repaired and replaced the mentioned part on time.