In the recent years, the all-wheel drive transfer system has been developed increasingly. This thesis mainly focuses on various means of AWD/4WD transfer case for active torque split. This paper mainly discusses about transferring torque into front and rear axles by different couplings. The first part of thesis illustrates several AWD/4WD transfer cases. In this step, the thesis shows description of each AWD/4WD transfer case. The second part, the paper shows the mathematic analysis about torque and rotational speed distribution of input, front and rear axles for each transfer cases. In the third part, the paper presents. Simulink models of transfer cases in AWD/4WD vehicles.