AWD and 4WD sound similar in name, but they are very different. AWD is always active on most vehicles, while 4WD can be customized depending on the situation. A lot of people use the terms four-wheel ...
Engineering Explained on MSN

How 4WD works - four wheel drive

How does four wheel drive work? This video explains the workings of four wheel drive (4WD), and gives a definition in order ...
How does four-wheel drive work? A conventional, two-wheel drive car will drive one axle, using a differential to handle the difference in wheel speed when going around bends or driving over surfaces ...