THE calibration of the four-speed automatic transmission is unique to the Tribute, using a more aggressive shift schedule for quicker response. The manual transmission is a Mazda unit. The Tribute is equipped with an on-demand four-wheel-drive system. Called "Rotary Blade Coupling" it quickly activates when road conditions demand. The four-wheel-drive system automatically senses when the front wheels begin to slip and hydraulically transfers power to the rear wheels for improved traction. This transfer of up to 50 percent of the engine's torque ensures that additional traction is on hand when needed. An instrument panel-mounted switch activates an electro-magnetic coupling and allows the driver to lock the system in permanent four-wheel drive when driving on slippery roads.