Identification of the Abnormal Noise in the Transmission of a Domestic Car and Its Redesign

A domestic car makes an abnormal noise under the neutral idling condition.A series of experiments are designed to find the possible noise source.Through spectrum analysis the input shaft bearings are identified to be the main transmission noise source.Taking into consideration the structural characteristics of the transmission,the input shaft bearings are replaced,and the noise is significantly reduced and the noise quality is improved.