The Jeep Liberty (2002+ Jeep Cherokee)
- 2008-2012 Jeep Liberty
- The 2005+ Jeep Liberty
- See the Jeep Liberty being built (factory tour)
- How the Jeep Liberty factory was designed
- Allpar's Jeep Liberty Limited review
- Allpar's Jeep Liberty Renegade review
- Guest editorials: Liberty vs Cherokee.
- Jeep Cherokee/Liberty forum
- Liberty vs Isuzu Rodeo Sport
Jeep Liberty design overview
The first redesign of the Jeep Cherokee “XJ” ended up being more upscale than the original; and Chrysler, which had just taken over AMC, decided to keep the old Cherokee while making the new one the “Grand” Cherokee. The second redesign (“KJ”) was first to replace the aged Cherokee; then the company renamed it Liberty, thinking it would keep Cherokee in production still. That lasted for around two months, and then Liberty stood alone. [Liberty development opinion].
From 2002 to 2004, 75% of Jeep Liberty buyers were new to the Jeep brand.
At luanch, there were two trim levels, Sport and Limited Edition. The front was designed to be unmistakeably a Jeep; two concepts were floated during development, the 1998 Jeepster and the Dakar.
The instrument panel used round dials cluster with black-on-beige graphics; round air outlets provided quiet air flow. The Limited Edition added satin chrome highlights. and slate-and-taupe leather seats. Bottle holders for rear passengers were molded into the doors, while front seat backs had map pockets (Limited only).
A 65/35-split rear seat with one-handed folding operation maximizes passenger and cargo flexibility. Shopping bag holders and child seat tether anchors are integrated into the back of the rear seats. The cargo floor has flush mounted, robust cargo tie downs.
Jeep Liberty drivetrain
Outside of North America, a 2.5-liter PowerTech common rail direct injection turbodiesel is available. It has nothing in common with the 2.4 or the 3.7. The 2.5 was later replaced with a 2.8 diesel engine - which finally made it to the US in 2005.
The base transmission was a five-speed manual until 2005 when it shifted to six speeds.
Early information told us that the 2.4 engine would come with the 42RLE four speed automatic, while the 3.7 would come with the Grand Cherokee's smooth-shifting five-speed. However, it currently appears that the 2.4 engine only comes with a manual transmission, while the 3.7 comes with the five-speed manual or the four-speed 42RLE automatic. The 42RLE transmission does not use Dexron - it requires Chrysler ATF+4 or compatible - so be careful and don't believe your oil change place if they say Dexron will work. The diesel comes with the Chrysler 545RFE five-speed automatic.
Part time four wheel drive is handled via Command Trac ® and full time four wheel drive goes through the optional NV242 Selec Trac® . The 45RFE five speed automatic transmission is available only on the Limited Edition model - if you can buy it, we recommend it over the four-speed.
The four speed automatic is a variation on the one used in Chrysler cars since 1989, adapted for rear wheel drive use. It was later used in the LX cars with V6 engines.
The NV3550 manual transmission has been updated with a reverse lockout from fourth gear, a quieter clutch disc, and longer, lower-rate damper springs to cut vibration.
The five-speed automatic is a pleasure to drive, and provides a 5,000 pound towing capacity. Details are here.
The Command Trac® and Selec Trac® transfer cases include stronger main shafts to absorb higher torque peaks. A needle bearing on the shift mechanism reduces shift effort and improves shift feel. With manual transmission-equipped vehicles, a rubber-isolated torsional damper on the transfer case output shaft makes for quieter transmission performance. Off-road capabilities for these drivetrains in low gear include calibrated vehicle crawl speed and engine braking on grades.
Jeep Liberty manufacturing
Chrysler's newest assembly facility, the Toledo (Ohio) North Assembly Plant (TNAP), follows the old Corporation's policy of "brownfield" construction which provides jobs where they are needed, while reducing minimal environmental impact. The plant is a showcase for best practices, employing at peak 1,900 employees to produce 800 units per day (two shifts).
Statistical process controls and performance feedback systems (PFS) feed continuous improvement and halt production if quality build criteria are not met. For example, if a bolt isn't tightened to the degree specified (measured through the torque wrench that is connected to the computerized PFS system) the specific operation will shut down until it has been corrected. Vehicle inspections throughout the process and final tests should improve J.D. Power standings and prevent many problems from reaching customers.
Suppliers were heavily integrated into the design of the production process and facility, as were Mercedes engineers. As with Chrysler's Windsor plant, production can be very flexible, so that different types of vehicles can easily and cheaply be produced. More than one carline can be produced simultaneously.
Safety - Jeep Liberty / Jeep Cherokee
Jeep Liberty features several braking system enhancements to deliver even more safety, durability and performance. Since heat is one of the biggest contributors to premature brake wear and loss of braking effectiveness, Liberty brakes were heat-tested in the parched desert of Death Valley, California, and in the grueling stop-and-go rush-hour traffic of Los Angeles. Major improvements over previous brake systems include larger, more robust rotors and drums and greater cooling capacity. The result is reduced brake fade (the loss of braking effectiveness as brakes heat up) and a longer life for Liberty's brake linings.
An available integrated anti-lock braking system (ABS) includes Electronic Brake Distribution (EBD), which automatically distributes braking forces between the front and rear axles, depending on how they can be used best, and adapts to variations in road surface and vehicle load. The system can be used off-road, since it allows for limited wheel lockup as needed, such as when the vehicle is descending steep sand or gravel hills. Liberty's ABS also is designed to limit false activation on bumpy surfaces, such as at railroad crossings and on the rough "washboard" surfaces of gravel roads.
Driver and passenger front air bags are designed to activate at different levels, depending on the severity of an impact and whether the occupant is buckled in. Liberty is the first Jeep with available side air bag curtains. The bags are designed to work independently of one another, only deploying on the side required.
Liberty represents the first Jeep vehicle to use three-point lap and shoulder belts in the middle rear seat. In addition, Liberty is equipped with the LATCH (Lower Anchors and Tethers for Children) system for mounting the new generation of aftermarket infant child seats that make it unnecessary to use the seat belt to secure an infant child seat. With the LATCH system, child seats attach directly to the structure of the rear seat, so they are easier to install and more secure.
Exclusive to Jeep, Liberty's "uniframe" construction incorporates all of the strength and durability of a body-on-frame construction into a unitized construction. By adding stiffness and rigidity to the structure, they enhanced the ride and strengthened the network of steel beams, rails and pillars (or "safety cage") that surround and protect occupants. More than 70 percent of the underbody is high-strength steel.
The 2002 Jeep Liberty has a number of new features designed to enhance occupant protection in the event of a collision. The engine cradle's rear fasteners are designed to give way in a severe frontal impact, which helps dissipate impact energy so it is diverted from the passenger compartment. Underbody rails that run the length of the vehicle are built with high-strength alloy steel and work with other structural components to reduce intrusion into the passenger compartment and help keep the fuel system intact. High-strength steel body-side components and reinforcements further help to protect drivers and passengers and maintain the shape of the doors in the event of an offset frontal impact.
Liberty has the highest roof strength of any Jeep vehicle. The rear gate opening's reinforcement assembly reduces the amount of crush to the passenger compartment in a rear-end collision. Engineers designed a rear cross-member beam to handle the load of the rear-mounted spare tire in a rear impact. This extra load would be too much for many traditional cross-member designs, so engineers used an ultra-high strength material. This heat-strengthened and tempered bumper beam is welded to the rear of the underbody rails.
Inside, the 2002 Jeep Liberty provides enhanced features designed to protect occupants including molded, structural foam in the headliner and concealed molded ribs under the pillar trim and shoulder belt turning loop trim.
Jeep Liberty's independent front suspension
The most controversial aspect of the Liberty is the independent front suspension.
Eight-inch suspension travel helps off-highway performance.
Cast iron lower and forged steel upper control arms, coupled to a cast iron steering knuckle via permanently lubricated ball joints, provide a stable base for the independent front suspension. This reduces the unsprung weight, allowing the wheels to track over bumps more easily. It also reduces wheel hop with four-wheel drive engaged on soft or loose surfaces.
Dual-rate lower control arm bushings provide crisp handling with low harshness. "Rate plates" molded into the bushings increase lateral stiffness for precise handling, while allowing longitudinal compliance to reduce the harshness of impact over bumps.
A new aluminum housing, designed for use with the independent front suspension, contains an enhanced Dana Model 30 center section. Larger pinion stem and bearing diameters and an increased ring gear diameter improve noise, vibration and harshness control and durability. Rubber-isolated mounting of the axle housing to the engine cradle helps keep axle and drivetrain noise and vibration from reaching the body structure.
Concentric coil springs and shock absorbers mount above the upper control arms for protection from off-road hazards, and to allow a tight turning circle. They connect to the lower control arm via rubber isolated forks through which the half shafts pass. A dual-path upper mount on the body structure has different rates for the coil spring and shock absorber to provide effective noise and harshness isolation. Upper and lower spring seat cushions further isolate the passenger compartment from road, axle and suspension noise. Computer selected springs maintain the desired ride frequency, vehicle height and stance regardless of equipment.
Liberty features a link-coil solid axle rear suspension, similar to Grand Cherokee. A trailing A-shaped upper arm, dual trailing lower arms, coil springs and a stabilizer bar control rear axle movement to provide a smooth, comfortable ride. The ride is enhanced by coil springs, which have less static and dynamic friction than leaf springs. With a roll center closer to the vehicle's center of gravity, this set-up reduces body lean during cornering. The "A" arm's sturdy, box section construction, tuned to provide extremely high stiffness, prevents transmission of axle and road noise. The "A" arm attaches to the axle through a single, lubricated-for-life ball joint atop of the rear axle differential housing.
Box section lower control arms contribute to precise axle location and good durability. Large, voided rubber bushings at the axle end of each control arm allow axle recession to reduce impact-bump harshness. The high stiffness of these control arms also reduces axle noise transmission. Progressive rate springs provide a consistently comfortable ride and help maintain consistent handling over varying load conditions. They also reduce the vehicle's ride height with load. Rubber upper and plastic lower spring seat isolators reduce road, axle and suspension noise transmitted to the passenger compartment. Different springs are used depending on the vehicle options.
A linkless rear stabilizer bar bolted directly to the lower control arms eliminates a noise transmission path into the body structure.
2003 Jeep Liberty (Cherokee) Changes
The Renegade Premium model gained dual power leather seats, premium interior, and an overhead console. Four-wheel disc brakes and full-size spare matching wheel were standard on all models.
What the Liberty could have been (Bob Sheaves)
I am one of those rabid Jeep fans that hates the KJ, for what it is. There was an opportunity to showcase a good independent front suspension (IFS) and the management blew it. If you remember back before it was introduced, I was a supporter of the car, because I knew what Chrysler had on the shelf (from the "King Of The Hill" prototype) and didn't think the management ignorant enough to NOT use it. Unfortunately, I was wrong and the "little girl's car" that debuted was a mess. All it would have cost was another $70 per vehicle (yes, that's a lot, but IMHO, the cost was justified-you don't see new HMMWV's running around under $100K today and the KJ could have had that much mobility).
The one bright spot for me is the Rescue show car-I know from my work on the Dodge Ram 4 link over constrained system, that this vehicle is (again, for me only-I am not telling anyone their ideas are wrong) a ray of hope and lust (amazing what yanks my crank, ain't it?) because of the air springs, long travel, AAM axles, and the possibility of an inexpensive (relatively speaking, of course-for home installation) of a CTIS system. All of this wrapped in a basic (meaning simple construction) body that is free of frilly plastic and junk (obviously, I am discounting the wannabe lamps built into the roof rack-another useless affectation from Design Office).
What many off roaders forget (or never knew) is that Jeep, in 1962, invented the first independent front suspension (IFS) for an off road vehicle in the US [Wagoneer] and offered it as an option.
The suspension Evan Boberg talks about in his book started out as the 1962 Wagoneer suspension-that was the genesis of the improvements...
My disgust with the KJ comes from the half-hearted job done on the IFS. Personally, I don't care what suspension is used, as long as it performs to the intended goals and parameters. In this respect, I have to admit the KJ does well-it was designed as a "girl's Jeep"...people may not like this characterization, but nontheless, it is quite accurate in describing the performance parameters. Jeep had, on the shelf, a design that would make the currect suspension seem as antiquated as the hotchkiss used on the CJ's, when looked from a technical standpoint. Unfortunately, there are only about 20 people in toto that have driven this kind of suspension, and 4 of them are NOT from Chrysler (I built a more advanced version of the KOTH Jeep suspension for a friend of mine under a Chevy full size Blazer (the GMT 400) that had 18" of wheel travel and a stock track width).
Unfortunately also, people that are not suspension engineers tend to be a bit ignorant about the pros and cons of variuous designs, hence the fear (justified in some cases) that the Jeeps will be "screwed up". by people (meaning the design and engineering staff of the controlling company) that have no idea what a Jeep is. These types of people generally cling to some perverse idea that change is bad-I agree with you on the statement, but not the reasoning there. What people need to understand is the the word Jeep, since it's inception, has ONLY meant one thing and one word....
The history of Jeep has never been centered aroung "change" but rather using the most defined parameters (it started with the military as "everyone knows"- but I would bet any amount of money that not 1 in 10 "experts" can list even 5 of the original military mobility requirements. Jeep has always been a purpose built vehicle-it has ALWAYS hit the intended target. That is not to infer that the targets were acceptable to the marketplace (the FC's and the KJ are 2 different examples of bad targets that were hit and while one failed, the other has been prosperous). Until a good independent suspension is manufactured in the general marketplace and people try it....change will always be viewed as bad.....
The suspension I am describing is one that, in addition to allowing the left and right tire to move independently of each other, allows the axle to move vertically as a percentage of the total wheel travel, the point is to allow the CV joints to be used for turning and power transmission without exceeding the limits of travel. What Evan described in the book (meaning comparing the HMMWV IFS/IRS to a Jeep Link/coil) demonstrates the limits of Rzeppa and tripod joint construction. This all means that a conventional IFS is limited to 8" of vertical travel, in general with a fixed axle, as used on the KJ. With the "floating axle" design this can easily increase to 12" and more, IF the length of the control arms is optimized. It predates the Kinetic system, which is marketed by Tenneco Automotive now.
You can search the US Patent office for "Evan Boberg" and call up the patent and drawings for this design to get an idea how it works.
Jeep Liberty Steering
Liberty is the first Jeep vehicle to offer rack and pinion steering. Effort, feel and response are tuned to give the driver precise control and positive feedback regarding the steering force exerted by the tires.