This paper describes the application of CAE tools in the design optimization of a DCT and driveline system of a passenger vehicle, with emphasis on NVH performance. The multi-body dynamics simulation tools are employed for driveline system analysis. The MBD model consists of the engine, transmission, clutch, drive shafts, tires and vehicle. The wheel slip effects are considered in the calculation of shuffle frequencies.In the analysis of gear whine, the transmission housing, gears and shafts are modeled by detailed 3-D finite element models, so that the mesh stiffness of the gears and the housing support stiffness are described more accurately. The calculated velocity spectra of the housing are presented.The prediction of gear rattle in the transmission is carried out. The loose gear acceleration index and the averaged impact power of free gears are calculated to assess the rattle generation potential and the level of rattle severity. The influence of the clutch spring rate and the gear backlash on rattle behavior is investigated.The dynamics of a new parking brake of the DCT is simulated. The parking brake lever force and shift torque in relation to shift angle are predicted. The shift contour of adjustment lever is optimized for better shift feeling and shift comfort. The model was validated through a comparison between the simulated shift torque and the measured one.