12-28-2013, 11:22 AM
A 4WD vehicle will split power and torque evenly between all the wheels (when 4WD is selected) whereas an AWD vehicle is a little smarter and will automatically adjust the torque to the wheels depending on which wheel has the best grip. As Obie pointed out, however, the real reason you want a 4WD vehicle is for driving down on the dirt road as you can select low-range and have the engine brake the car for you. There have been several accidents caused by visitors and residents burning their brakes out on the way down. Our organisation has several 4WD vehicles and one AWD car, but we never drive the AWD vehicle above Hale Pohaku. Incidentally, it's good practise to switch back to 2WD when on the paved road since when 4WD is selected all the wheels turn at the same speed which makes cornering a problem.