If you ever decide to leave the beaten path to see nature in its full glory, you could dedicate years to physical training and conditioning to be a mountain climber, or you could buy a vehicle with four-wheel drive. Kudos to those who have the time and willpower to climb mountains, but we choose the automotive route.Jeep would agree. Its four-wheel-drive vehicles are some of the most rugged, capable ways to get where humans haven't paved paradise.Not all 4WD systems are the same, though. Jeep is one of the best-known names in off-roading, and it even offers five variants of its 4WD system. The Wrangler offers three types of 4WD alone, with the Rubicon trim level reaching peak capability from the factory.Let's take a closer look at what four-wheel drive really means, the basics of a transfer case, and then discuss in detail every type of 4WD system Jeep offers. Before you hit the trails on your own, it's important to know what your vehicle is really capable of and how to use the technology.All specifications have been gathered directly from the manufacturer. Off-roading is inherently dangerous; follow all manufacturer-recommended guidelines, and CarBuzz recommends not driving alone. What is 4WD: Transfer Case Basics The Fundamentals That Make Jeeps Capable JeepA transfer case is an essential part of any four-wheel-drive vehicle that helps route power to the appropriate axle. Power from the engine runs through the transmission and then goes to the transfer case. There are multiple types of transfer cases, including full-time and part-time versions. Full-time 4WD vehicles direct power to both axles at all times. Vehicles with part-time 4WD come with a button, lever, or another way to switch manually between 2WD and 4WD. However, 4WD should only be engaged on low-traction surfaces to prevent drivetrain binding.Even though this article is about Jeeps, a great example of a single model that was available with every type of transfer case is the third-generation Toyota 4Runner."The Jeep brand is one of the world leaders in 4x4 technology—it’s the backbone of the brand. Our sophisticated 4x4 systems let you find your own way up, down, through, or around almost anything. You can trust the Jeep Brand with its 80-plus years of 4x4 excellence to help you tackle nearly anything Mother Nature sends your way."- Jeep Jeep's 4x4 Systems: Command-Trac Current Models With This System: Wrangler, Gladiator JeepJeep's Command-Trac is a part-time four-wheel-drive system available on the Wrangler and the Gladiator midsize truck. It features both high and low-range gears to tackle most low-traction scenarios with the NV241 GII transfer case. Drivers can shift from RWD to 4HI (four-wheel drive with high-range gearing) while driving at up to 55 miles per hour, and back to RWD. This system locks power to both axles with a 50/50 split when engaged. 4LO (four-wheel drive with low-range gearing) can't be engaged while driving, and should only be used at low speeds when necessary. Using this function means power is sent through another set of gears, multiplying torque to 2.72:1. Selec-Trac Full-Time 4WD System Current Models With This System: Wrangler, Gladiator Stellantis North AmericaIf you don't want to engage 4WD manually, the Selec-Trac full-time 4WD system may be a better fit. In this full-time 4WD system, drivers can feel confident at all times — even on dry pavement. Unlike part-time systems that require manual shifting into four-wheel drive, Selec-Trac automatically senses slick conditions and shifts into 4WD without the driver lifting a finger. It uses the same gear ratios as the part-time system above, and drivers can still engage the four-wheel-drive system when they want. For the Most Intense Crawling: Rock-Trac 4x4 Current Models With This System: Wrangler, Gladiator Stellantis North AmericaOnly the most extreme versions of the Wrangler and Gladiator get Jeep's Rock-Trac branding, which is standard on the Rubicon trims of both models. It's unique because the automaker offers versions with either part-time or full-time functionality, allowing buyers to choose their preference.No matter which version you choose, though, the best part about Rock-Trac is its 4:1 low-range gear ratio. When low-range four-wheel drive is engaged, torque is multiplied four times to help slowly crawl over large boulders and other obstacles. The part-time variant of this system has manually operated high and low gears, while the full-time version adds a 4WD Auto mode that detects low traction and shifts on its own. Quadra-Trac And Quadra-Drive 4WD Systems Current Models With This System: Grand Cherokee JeepSome Jeep Grand Cherokee models are equipped with a system called Quadra-Trac, which is available in two versions. Quadra-Trac I is essentially an all-wheel drive system with a single-speed transfer case. Power is split through a center differential, with 48% to the front axle and 52% to the rear. It works in a "full-time high-range" mode that doesn't require any driver input. Quadra-Trac II features a two-speed transfer case with high- and low-range gears. Quadra-Drive II 4x4 System Brett T. Evans/CarBuzz/ValnetQuadra-Drive II is more advanced than the previous two systems, adding a rear electronic limited-slip differential and other upgrades. Up to five drive modes, including auto, sport, snow, sand/mud, and rock, can automatically adapt to your situation. This is still a full-time four-wheel-drive system with high- and low-range gears. Jeep Active Drive 1, 2, And Lock Systems Current Models With This System: Compass JeepThe current Jeep Compass and the old Cherokee use a system called Active Drive, which comes in multiple versions. These are technically full-time 4WD systems that automatically detect low-traction surfaces to send power to both axles when needed, but they operate differently from Selec-Trac. Firstly, the Compass usually sends power to the front wheels rather than to the rear axle. The Lock system offers more control by allowing the driver to lock the rear axle. In addition to these systems, Jeep offers the Active Drive Low 4x4 System on the Compass, which adds a 20:1 crawl ratio and low range for extra capability. Selec-Terrain Traction Management System Current Models With This System: Wagoneer S Jared Rosenholtz/CarBuzz/ValnetJeep might be a go-to brand for rugged, mechanical capability, but even this automaker is dabbling in EVs. The Wagoneer S electric SUV puts greater emphasis on comfort and easy driving than on off-roading. However, Jeep offers it with a standard system called Selec-Terrain that lets the driver choose a drive mode that best suits the conditions. Drivers can simply choose from a few drive modes, including Auto, Snow, Sand, Sport, and Eco, and the system can automatically choose how much power turns the front or rear wheels. Most Jeeps are Off-Road Capable, but They're Not all the Same JeepWhether you're off-roading or overlanding, knowing when and how to use your four-wheel-drive Jeep is vital to staying safe and maintaining traction. To wrap up, we'll remind you of some basics: part-time four-wheel-drive systems like Jeep's Command-Trac should only be engaged on low-traction surfaces, since the drivetrain and transfer case can bind while turning on dry pavement. Full-time 4WD systems like the Selec-Trac system can automatically detect when you enter a low-traction environment and decide when to send power to both axles on its own. Not all 4x4 systems are the same, and knowing when and how to use them could get you out of a pickle one day.Sources: Jeep
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