autoevolution
Car video reviews:
 

Jeep's AWD and 4WD Systems Explained

Jeep is a brand known for its off-roaders, and the company has over ten variations of its 4x4 systems in its offering in 2016.
2014 Moab Easter Jeep Safari 7 photos
Jeep's current portfolioSelec-Terrain switch on 2014 Jeep Cherokee Limited2016 Jeep Compass2015 Jeep Renegade Trailhawk2016 Jeep Wrangler Unlimited 75th Anniversary2015 Jeep Grand Cherokee Summit
The systems that Jeep provides work in different ways and have sketchy names, which often confuse people. For example, some of them are called Active Drive, Freedom Drive, Quadra-Trac, Selec-Trac, and Quadra-Drive. Confused, yet?

Well, we want to help you understand what’s going on in the Jeep lineup, so we put together this article concerning the company's four-wheel-drive and all-wheel-drive solutions.

Jeep also has an all-wheel-drive switch called Selec-Terrain, which has up to five settings. It comes standard on all Cherokees with AWD, and on all Grand Cherokees with a two-speed transfer case, as well as Renegade models.

Before we get started, we need to clarify one aspect: 4WD is not technically synonymous with all-wheel-drive. The former is the most rugged form of four-wheel-drive, and is not necessarily always on. However, it comes with improved performance on rough terrain and in low-grip conditions.

If you are looking for an off-roader, it's safe to say that you need something with 4WD. Meanwhile, all-wheel-drive is almost always on and typically sends power to all four wheels. Since it is controlled by a computer, it allows the automaker to customize the way power is delivered to the wheels, and to fine tune how the vehicle handles. In spite of doing the same thing as 4WD in theory, all-wheel-drive is not as well-suited for off-roading as a conventional 4x4 system.

Jeep sells both systems, but they are marketed differently. Naturally, some models do not come with a 4WD system, but have all-wheel-drive, while the opposite is true for other Jeep cars.

You can buy a Jeep with an all-wheel-drive system and order an improved 4WD solution for certain engine versions, but this applies only to some models in the range.

In extreme off-road conditions, 4WD beats AWD any day, but each system comes with a set of advantages and disadvantages. Except for an off-road fanatic, an all-wheel-drive system should be just fine for the regular user. All-Wheel-Drive Systems for Cherokee and Renegade
We will start with the Active Drive system, available on the Jeep Renegade and the Cherokee. This system requires no input from the driver, and it comes with a set of sensors that determine whether to send power to the rear wheels or just to the front axle. If a slip is detected in the front wheels, the rears get power until the speeds are matched.

This system is an all-wheel-drive solution, and it has several operating modes to enhance its capabilities. It comes in versions like Active Drive Low, Active Drive I, Active Drive II, and Active Drive Lock. The first of these features a low-range switch, and it's only available for the Renegade Trailhawk. It has a 20:1 crawl ratio.

Meanwhile, Active Drive I is only offered on the Cherokee. The system works just like on the Renegade 4x4, but has a different name. The Active Drive II can be had on the Latitude and Limited versions of the Cherokee and comes with a low-range function. Unlike the one on the Renegade, this one has a 56:1 crawl ratio. It also offers a “neutral model,” used for flat towing.

The Active Drive Lock comes as standard for the Cherokee Trailhawk. It represents an evolution of the Active Drive 2 and features an extra mechanical real axle lock. The crawl ratio is maintained and the system also benefits from Jeep’s “Trail Rated” guarantee of off-road performance.4WD Systems for the Jeep Wrangler
Command-Trac 4x4

The name Command-Trac dates back to the 1980s. It is a classic 4x4 solution, and it is so hardcore it cannot operate in 4WD mode on high-traction surfaces, like dry pavement, because it would suffer excessive wear as it does not have any differential action in the transfer case. It is recommended for wet/slick surfaces, extreme weather, and off-road activities.

Its transfer case comes with a shift-on-the-fly system, and users can opt for a neutral range for flat towing, or a 2.72:1 Low range, used for extreme off-road situations.

Different variations of this system are in use today, and you can find the Command-Trac on the Wrangler/Wrangler Unlimited Sport, Sport S, and Sahara Trims.

Rock-Trac

This system comes standard for the Wrangler/Wrangler Unlimited Rubicon. It has locking differentials with electronic actuation and offers an electronic front sway bar disconnect function (introduced in 2007). The latter allows for impressive off-road abilities and is only found on this system.

Additionally, it comes with an NV241 OR transfer case, which provides a 4:1 low gear ratio. Naturally, it is “Trail Rated,” and it has a brake lock differential.

Rock-Trac is the hardcore version of Jeep’s 4x4 systems. In principle, it works like the Command-Trac system, but it has a few extra solutions, as mentioned above. The Command-Trac has formed a base for the Selec-Trac and Quadra-Trac systems.All-Wheel-Drive and 4WD Systems for the Jeep Grand Cherokee

Quadra-Drive II 4x4 & Rear ELSD


The only Jeep model to use Quadra-Drive II is the Grand Cherokee, and the system is optional for the Limited, Overland, and Summit trims. It has five operating modes, and can be mated to an air suspension system for improved off-road ability. The ELSD mentioned is an electronically controlled limited-slip rear differential. The front axle has an open diff.

Quadra-Trac I 4x4


Customers of the Grand Cherokee get the Quadra-Trac I system as standard with the Laredo trim level. Unlike others, this is always on and comes without any buttons or levers. It does have a brake lock differential, and is factory-ready for a small amount of off-roading, as it is an all-wheel-drive solution.

Quadra-Trac SRT 4x4

The SRT Grand Cherokee gets the Quadra-Trac SRT variant of the system. It comes with a strengthened transfer case to withstand the increased output and torque, as well as an E-LSD at the rear, capable of sending 100% of available torque to one of the wheels. It also has a mechanical “wet” clutch, and comes with a five-mode Selec-Trac system for choosing between operating modes in off-road conditions.

Quadra-Trac II 4x4

Customers of the Limited, Overland, and Summit trim levels of the Jeep Grand Cherokee get the Quadra-Trac II system as standard. It can be ordered as optional equipment for the Laredo.

Unlike the Quadra-Drive II, the Quadra-Trac II has a two-speed transfer case, which Jeep says it can deliver up to 100% of available torque to the axle with the most traction. This is done using sensors in each wheel to check for grip. It comes with a Selec-Trac dial with five operating modes. Its 4WD-Low range is of 2.72:1, and has a neutral function for flat towing. It works with four-wheel brake traction control and a brake lock differential.

Out of the two systems available for the Grand Cherokee, the Quadra-Trac II is the most capable version in off-road driving.All-Wheel-Drive Systems for the Jeep Compass and Patriot
Just like the Active Drive, the Freedom Drive system from Jeep is only suitable for light off-roading and does not require any driver input. The Freedom Drive I is electronically-controlled and rides mostly on the front wheels. It is standard for the Compass in Sport/Latitude/High Altitude trims, as well as the Patriot in the mentioned equipment levels.

Freedom Drive II 4x4

The FD II brings a bit more capability to the Freedom Drive system by using a CVT2L transmission with an off-road mode. It comes with a 19:1 crawl ratio. It is better in off-road conditions than the Freedom Drive I, but it is no Rock-Trac, mind you. The Freedom Drive II is available as optional equipment for the Sport and Latitude trims of the Compass and Patriot.

The Freedom Drive 2 system also comes with Jeep's "Trail Rated" guarantee of performance in off-road conditions. However, do not confuse that with the abilities of a Wrangler, as it is on the Compass.



 
 
 
 
 

Would you like AUTOEVOLUTION to send you notifications?

You will only receive our top stories