Four-wheel-drive is a must-have for cars, trucks, and SUVs that encounter rough road conditions. However, it is important to know the difference between the two major settings on four-wheel-drive vehicles. To help you learn more, we explain the difference between four-high (4H) and four-low (4L) drive modes. If you encounter rain, slick roads, light snow, loose gravel or tightly packed dirt or mud, then you will want to set the four-wheel-drive in the 4H mode. This mode will give your vehicle more traction but allow you to drive at normal speeds. Most of the time you will be using the 4H mode. When you come across heavy snow, heavy rain, thick mud, high water, rocks, and steep inclines, then you will want to select the 4L mode. This four-wheel-drive mode will apply more torque to the wheels and provide more power. In 4L mode, the wheels will spin more slowly to provide more grip on the driving surface.