Some modern trucks and SUVs have a drivetrain mode called 4WD Auto. What does this mode actually do, and how does it work?

Although they may sound similar, AWD and 4WD are built for very different driving conditions—here's how they actually work ...

How does 4WD work? What to look for when buying a used 4x4 The origins of 4WD How does four-wheel drive work? A conventional, two-wheel drive car will drive one axle, using a differential to handle ...