Engaging four-wheel drive in a Jeep involves shifting the transfer case from two-wheel drive to a four-wheel drive mode. This redirects power from solely the rear or front wheels to all four wheels, enhancing traction. For example, a Jeep Wrangler often employs a lever to select between 2H (two-wheel high), 4H (four-wheel high), 4L (four-wheel low), and sometimes neutral (N). Different Jeep models may utilize a part-time or full-time four-wheel drive system, influencing how and when the system should be engaged.
Enhanced traction in challenging conditions, such as off-road terrains, snow, or ice, is the primary advantage of employing four-wheel drive. This capability has a long history linked to military vehicles and their need for reliable performance in adverse environments. Over time, this technology transitioned to civilian vehicles, providing drivers with greater control and safety on slippery surfaces and uneven terrain. The choice of which mode to engage (4H or 4L) depends on the specific situation. 4H is generally used for higher speeds on less demanding surfaces, while 4L provides greater torque at lower speeds for challenging obstacles and steep inclines.