It does not have a Torsen. The center differential is a computer controlled clutchpack that locks and unlocks based on information from a number of different sensors and systems. According to the shop manual the AWD system is cabable of sensing the need for awd before spin takes place (unlike reactionary systems) so it sounds like something may not be working correctly with yours. If there is no error message (AWD deactivated), I would have a dealer check it out. There are certainly a number of sytem tests in the shop manual that can be performed.