Recently, automotive are used not only as a means of transportation, but also as a private and leisure spaces. In order to secure competitiveness in the automobile market, we must improve durability and noise/vibration technologies. The driver wants to keep quiet even if the car is used for a long time. The types of noise and vibration generated by the automotive can be divided into NVH and BSR. NVH should be reduced because it is caused by mechanical defects and aging. In this study, it was possible to accurately analyze the cause of noise and vibration, also it could identify the location, and repair that. In the future, research of an abnormal and vibrations such as NVH and BSR in automotive is needed to clearly identify.

In the case of a rear-wheel drive vehicle, a propeller shaft is installed to transmit the driving force of the engine. At this time, the propeller shaft is divided into 2 or 3 pipes, and the bearing is mounted on the vehicle body. And the end of the propeller shaft is connected to the rear differential and connected to the body through the chassis. Due to this complex structure, the propeller shaft must be highly balanced and the mounting angle must be well maintained. However, depending on the driving conditions of the car, various noise and vibration problems occur due to the aging of the parts and the propeller shaft. Hyundai Motor Company's maintenance center uses 'Noise Observer' to resolve various noise and vibration customer complaints. This paper describes the mechanism of vibration problems caused by unbalance of the propeller shaft and the diagnosis process using a 'Noise Observer'.