And then there are full-time AWD systems — typified by Subaru’s Symmetrical All-Wheel-Drive and Audi’s Quattro — that always transfer power to all four wheels. Depending on the system, the torque distribution can be rear-biased, front-biased or, as in the case of Subaru, a 50/50 split. Even so, how they distribute power varies from manufacturer to manufacturer. Audi, for instance, uses a Torsen system in its centre differential, while Subaru uses either a mechanical viscous clutch (for manual transmission models) or a more sophisticated electronic version on CVT-equipped Foresters and Outbacks. Either way, what separates full-time AWD systems from their lesser part-time alternatives is that they always send a significant portion of the engine’s power to all four tires.