Jeep's AWD and 4WD Systems Explained

Many automakers use said terms interchangeably because 4WD and AWD are both designed to distribute torque to all four wheels. In most applications, all-wheel drive is always on. Four-wheel drive, on the other hand, usually implies a two-wheel-drive mode such as 2H. Part-time AWD does exist, and the same can be said about full-time 4WD, which is also called adaptive 4WD.

All-wheel drive such as the Haldex- and Torsen-style Audi quattro systems are primarily designed to improve a vehicle's on-road characteristics. Four-wheel drive is more at home off the beaten path. The JL-generation Wrangler, for example, comes with three 4x4 systems in the form of the Selec-Trac, Command-Trac, and Rock-Trac.

Before the Jeep brand started naming its four-wheel-drive systems, Jeep models relied on the Dana Spicer 18 and 20 gear-driven transfer cases. Willys–Overland started using the part-time Dana Spicer 18 with the Willys MB in the 1940s, which features two sticks. The lever on the left is for disengaging the front axle in forward mode and to engage the front axle in rear mode, whereas the passenger-side lever is for low and high range.

Now that we've cleared the basics, we should get down to explaining Jeep's branded all-wheel drive and four-wheel drive systems. To keep it nice and simple, we'll go through them all in chronological order, beginning with the Quadra-Trac of 1973.

Quadra-Trac (introduced in 1973)

Quadra-Trac was deployed to the Wagoneer, Cherokee, and Gladiator when American Motors Corporation was calling the shots. Come 1976, the CJ-7 also received the Borg-Warner BW1339 transfer case. Four years later, American Motors switched Quadra-Trac to the NP219 transfer case, with NP being a reference to the supplier, namely the folks at New Process Gear. The company would be renamed to New Venture Gear back in 1990.

Rolled out in 1980 with a viscous limited-slip coupling, the NP219 equipped a plethora of 1980 to 1982 models, including the SJ-series pickup truck, Wagoneer, Grand Wagoneer, and Cherokee. Its replacement was the NP249 of the 1993  through 1995 Jeep Grand Cherokee. For 1996, the Chrysler-owned marque upgraded the Quadra-Trac system to the NV249 transfer case. As for the main difference between it and its predecessor, that would be the 4WD Low mode's mechanical differential lock.

Quadra-Trac II followed suit in 1999 with either NV247 or NV246 transfer cases, while Quadra-Trac I eliminated the 4L and N modes of its forerunner. Both systems were used in the Grand Cherokee through model year 2021 and the XK-gen Commander through 2009. The Commander nameplate would be revived in 2021 for a mid-size crossover intended for South America, whereas Grand Commander is a China-exclusive affair.

Command-Trac (introduced in 1980)

Command-Trac is the basis of the Rubicon trim level's Rock-Trac system. It all started in 1980 with full-size models and the NP208 transfer case. Other cases include the NP207, NP231/NV231, the heavy-duty versions of the NV231, the NP231J HD the MP1522, and the NV241. Applications? Make that full-size SJ models from 1980 onwards, the XJ Cherokee and MJ Comanche, the ZJ Cherokee, the KJ Cherokee and Liberty, the KK Cherokee and Liberty, plus the Wrangler and the Gladiator.

The shift-on-the-fly transfer case of the KK-series Cherokee and Liberty simplifies operation by means of a console-mounted switch instead of a lever, but as you're well aware, Command-Trac still comes with a lever in the JL-series Wrangler and the JT-series Gladiator. The part-time system provides a 2.72:1 low range ratio and four operating modes, as follows: 2H, 4H, Neutral, and 4L.

Neutral is for flat towing behind another vehicle; two- and four-wheel drive high is for regular driving, but four-wheel drive low should not be used at speed. Useful when launching or loading watercraft, four-wheel-drive low is for off-road shenanigans. At the moment of reporting, Command-Trac is available only in the body-on-frame Wrangler and the Gladiator pickup truck.

Selec-Trac (introduced in 1983)

Twinned with Quadra-Trac NP219, the Selec-Trac system used NP228 and NP229 transfer cases to improve gas mileage with the addition of a rear-wheel-drive mode. Selec-Trac wouldn't have been possible without the Select-Drive NP129 of the AMC Eagle. As far as the Jeep brand is concerned, Selec-Trac debuted for 1983 in full-size models.

American Motors would improve Selec-Trac with the NP242 transfer case in 1987, the year Chrysler purchased the ailing manufacturer for approximately $1.5 billion. It goes without saying that Chrysler was mostly interested in all things Jeep, including Command-Trac and Quadra-Trac. The NP242 transfer case operates in a similar fashion to the NP228 and NP229, but makes it that little bit easier for the driver by means of a lever that bundles all the range and mode controls.

Selec-Trac II may be marketed as Selec-Trac, but it differs big time from the aforementioned version and Command-Trac. First of all, it's a full-time system with an electronically controlled clutch pack. Secondly, there's no center diff. For model year 2024, this full-time system comes by default in the HEMI-powered Rubicon 392. Regardless of application, the Selec-Trac II system uses a Magna Powertrain transfer case designated MP3022.

Quadra-Drive (introduced in 1999)

Quadra-Drive is a development of Quadra-Trac II. More specifically, limited-slip differentials for the front and rear axles make it far superior to Quadra-Trac II. How come? In addition to directing torque to the front and rear axles, Quadra-Drive also directs torque between a given axle's wheels.

Quadra-Drive combines the NV247 transfer case of Quadra-Trac II with gerotor pump-style differentials, which are known as Vari-Lok in Jeep vernacular. The WJ-series Grand Cherokee received this four-wheel-drive system in 1999, after which Quadra-Drive II rolled out in the WK/WK2 Grand Cherokee and the XK-series Commander. The Quadra-Drive II system features electronic limited-slip differentials and the NV245 transfer case. Beginning in 2011, the front limited-slip diff was replaced by an open differential. Rather than Quadra-Trac II, the 6.4-liter Grand Cherokee SRT and the Hellcat-engined Grand Cherokee Trackhawk use Quadra-Trac SRT.

An active on-demand 4x4 system, Quadra-Trac SRT is a single-speed design that includes a wet clutch and a rear electronic limited-slip diff for sending 100 percent of the drive torque to either of the rear wheels. For the fifth-generation Grand Cherokee, which is codenamed WL, your choices are Quadra-Trac I single-speed 4WD and Quadra-Trac II active 4WD with a two-speed transfer case. The Grand Cherokee 4xe is Quadra-Trac II as well, but more on all things 4xe a bit later.

Rock-Trac (introduced in 2003)

A great name for a garage rock band, Rock-Trac is derived from Command-Trac. The Rock-Trac system comes in either part-time or full-time flavors in the JL Wrangler and JT Gladiator.

Part-time 4WD is standard in the Wrangler Rubicon for the United States market, whereas the Rubicon X and 4xe are listed with the full-time system for the 2024 model year. The Gladiator cannot be had with anything other than the 3.6-liter Pentastar V6 for 2024, which is connected to either the Aisin AL6 manual or the ZF 8HP auto.

The AL6 is part-time 4WD exclusively, whereas the Torqueflite 850RE is full-time 4WD. Obviously enough, Rock-Trac is the most off-road-capable 4x4 system that Stellantis-owned Jeep offers for the 2024 model year. Rock-Trac was introduced in 2003 by the TJ-series Wrangler, back when the locking differentials were air-actuated. 2007 saw the introduction of the front sway bar disconnect feature and electric actuation for the diffs.

Freedom Drive (introduced in 2007)

Discontinued in 2017, the Freedom Drive all-wheel-drive system was exclusive to the MK-series Jeep Compass and Patriot. MK is another way of saying GS platform, a front-biased architecture developed by the peeps at DaimlerChrysler and Japanese automaker Mitsubishi Motors.

The MK designation was introduced after the dissolution of the partnership, with DaimlerChrysler making substantial changes to said platform for vehicles from the Chrysler, Dodge, Jeep, Fiat, and Lancia brands. An electronically controlled full-time AWD system, Freedom Drive I is perfectly suitable for light off-roading. Freedom Drive II adds more off-road capability with a continuously variable transmission and a lower axle gear ratio, along with off-road calibrations for the traction control and electronic stability program, hill descent control, longer suspension travel, and skid plates.

By simulating a low-range transfer case, Freedom Drive II offers a 19:1 crawl ratio. By comparison, the JL Wrangler Rubicon boasts 84.2:1 from the outset and 100:1 as an option. The Ford Motor Company's Bronco tops 94.75:1 with the manual box and the optional Advanced 4x4 system.

Selec-Terrain (introduced in 2011)

And now for something completely different. Monty Python references aside, Selec-Terrain is a traction management system introduced by the 2011 Jeep Grand Cherokee. Every model equipped with Selec-Terrain features a control dial with settings for diverse conditions. Auto automatically adapts to the on- or off-road situation; Snow is self-explanatory as well; Sport is for enhanced on-road fun, while Sand/Mud operates with a more sensitive response to wheel spin over loose surfaces.

Rock also needs to be mentioned. In the press release for the 2011 Jeep Grand Cherokee, the manufacturer explains that Rock mode coordinates the transfer case, diffs, and throttle while also raising the Quadra-Lift air suspension to the maximum height of 11.1 inches or 28.2 centimeters. In the Renegade 4xe and Compass 4xe for Europe, the Selec-Terrain dial includes Hill Descent Control, 4WD Lock, and 4WD Low.

Not available in the United States, the Renegade 4xe and Compass 4xe bring together a 1.3-liter turbo and two electric motors. The first motor is coupled to the engine and acts as a generator, whereas the second motor drives the rear wheels and recovers energy while braking. Said 4xe system is different from that of the Avenger 4xe. Although one is a unibody and the other is a body-on-frame sport utility vehicle, the Grand Cherokee 4xe and Wrangler 4xe feature the same powertrain.

Active Drive (introduced in 2014)

The KL-series Cherokee introduced Active Drive to the world, an all-wheel-drive solution with four variations. It requires no driver input, for the system continuously monitors what is going on with the front and rear wheels. In addition to the 2014 model year Cherokee, this all-wheel-drive solution also equips the 2015-and-newer Renegade, the MP-series Compass, and the Grand Commander.

Active Drive II adds 4L mode, resulting in a crawl ratio of 56:1 in the Cherokee with the 2.4-liter Tigershark and 47.8:1 in the Cherokee with the 3.2-liter Pentastar. Active Drive Low also comes with 4L, but its crawl ratio doesn't go higher than 21:1 in the Renegade or 20:1 in the larger Compass.

Active Drive Lock builds on Active Drive II with the addition of a locking rear differential and Rock mode for the Selec-Terrain rotary controller. In the Jeep Cherokee Trailhawk, it achieves 51:1.

4xe (introduced in 2020)

Having already explained what makes the Renegade 4xe and Compass 4xe tick, we should also peel the sheet metal off the Avenger 4xe, Wrangler 4xe, and Grand Cherokee 4xe. Produced in Poland, the Avenger 4xe is Jeep's take on the Alfa Romeo Junior Ibrida Q4, meaning 1.2-liter turbo three-pot and two electric motors.

The rearmost drive unit evidently drives the rear wheels, and as opposed to the plug-in hybrid Renegade 4xe and Compass 4xe, the Avenger 4xe is a mild hybrid that uses a relatively small battery. The 2.0-liter turbo four-cylinder Wrangler 4xe and Grand Cherokee 4xe are plug-in hybrids with large high-voltage batteries. From 17.3 kilowatt hours, they achieve an EPA-rated 22 and 26 miles (35 and 42 kilometers) of zero-emission range.

Grand Cherokee 4xe rocks Quadra-Drive II with a rear electronic limited-slip diff and front-axle disconnect. Unfortunately, the family-sized Grand Cherokee L cannot be had as a PHEV. The four-door-only Wrangler 4xe comes with full-time 4WD in the form of Selec-Trac or Rock-Trac.