Abstract: Using LS_DYNA， the finite element models of all shafts were established. Based on explicit dynamic method， the shaft vibrations were analyzed and the dynamic excitations of bearing parts were obtained. On these bases， the vibration noise of the boundary element model of the transmission shell was analyzed under bearing excitations and the surface noise distribution was obtained using the boundary element method. Thus a new method of the noise analysis for transmission was provided. The results show that the radiation noise mainly focuses on the differential and parts of the rolling bearing. To reduce the noise level， reinforcements should be added on the shell side or the thickness of the existing reinforcements should be increased.

Key words: automotive transmission, explicit dynamics, boundary element method, radiated noise, reinforcement