A four wheel drive assembly 10 including a torque transfer assembly 60 which operates under the control of the controller 62 and which receives and selectively transfers a certain desired amount of torque to a front axles 14, 15 and to the rear axles 14 17. The amount of transferred torque varies depending upon the occurrence of a sensed slip condition the use of a pre-emptive slip control mode of operation in which the controller 62 determines that it is likely that a slip may occur. Particularly, controller 62 is allowed to enter the preemptive mode of operation only after an actual slip has occurred and the controller 62 exits this preemptive mode of operation upon the occurrence of a certain event or condition or upon the passage of a certain amount of time.