Jeep Grand Cherokee

Development

The Grand Cherokee's origins date back to 1983 when American Motors Corporation (AMC) was designing a successor to the smaller Jeep Cherokee (XJ). Three outside (non-AMC) designers—Larry Shinoda, Alain Clenet, and Giorgetto Giugiaro—were also under contract with AMC to create and build a clay model of the Cherokee XJ replacement, then known as the "XJC" project. However, the basic design for the Cherokee's replacement was well under way by AMC's in-house designers and the 1989 Jeep Concept 1 show car foretold the basic design.

As AMC began development of the next Jeep in 1985, management created a business process that is now known as product lifecycle management (PLM). According to François Castaing, Vice President for Product Engineering and Development, the smallest U.S. automaker was looking for a way to speed up its product development process to compete better against its larger competitors. The XJC's development was aided by computer-aided design (CAD) software systems making the engineers more productive while new communication allowed potential conflicts to be resolved faster this reducing costly engineering changes because all drawings and documents were in a central database. The system was so effective that after Chrysler purchased AMC in 1987, it expanded the system throughout its enterprise, thus connecting everyone involved in designing and building products.

The Grand Cherokee thus became the first Chrysler-badged Jeep product. Development work for the new Jeep model continued and Chrysler's employees (after the 1987 buyout of AMC) were eager for a late-1980s release date; however, CEO Lee Iacocca was pushing for redesigned Chrysler minivans, thus delaying the Grand Cherokee's release until late-1992 as an Explorer competitor. Unlike the Explorer, the Grand Cherokee utilized monocoque (unibody) construction, whereas the Explorer was a derivative of the Ranger pickup with a separate body-on-frame.

The Grand Cherokee debuted in grand fashion at the 1992 North American International Auto Show in Detroit, Michigan. The vehicle that was driven was a Poppy Red Clear Coat 1993 Grand Cherokee ZJ Laredo with a quartz cloth interior and high-back bucket seats. Then Chrysler president Robert Lutz drove Detroit mayor, Coleman Young, from the Jefferson North Assembly Plant on North Jefferson Avenue via a police escort to Cobo Hall, up the steps of Cobo Hall and through a plate glass window to show off the new vehicle. Sales of the 1993 model year Grand Cherokee began in April 1992.

Production of the Grand Cherokee started shortly afterward in the purpose-built Jefferson North Assembly in Detroit, Michigan. European Grand Cherokees are manufactured in Austria by Magna Steyr. The Grand Cherokee "played a significant part in reviving Chrysler's fortunes by moving it into the then nascent market for high-margin sports utility vehicles."

Upon its introduction, it was the first USA-manufactured automobile using HFC-134a refrigerant in place of HCFC-12 for the HVAC system.

First generation (ZJ; 1993–1998)

The original Grand Cherokee was launched in 1992 as a 1993 model year vehicle in the luxury SUV segment. The "ZJ" models, manufactured from 1992 to 1998, originally came in three trim levels: base (also known as SE), Laredo, and Limited, subsequent trims were added, included Orvis (95–98), TSI (97–98). The base model included features such as full instrumentation, cloth interior, and a standard five-speed manual transmission, while gaining the moniker "SE" name for the 1994 model year. Power windows and locks were not standard equipment on the base trim. The minimal price tag differential resulted in low consumer demand, and as a result, the low-line model was eventually discontinued. Additional standard features included a driver-side air bag (starting in 96) and four-wheel anti-lock braking system (ABS). The Laredo was the mid-scale model with standard features that included power windows, power door locks, cruise control, and a leather wrapped steering wheel. Exterior features included medium-grey plastic paneling on the lower body and five-spoke alloy wheels. The Limited was the premium model, featuring body color lower body paneling, and gold exterior accents. The Limited also boasted standard features such as leather seating, heated mirrors, front power seats, a keyless entry system, wood grain interior appliqué, lace style alloy wheels, a driver information center with compass, digitized climate control, and electrochromic rearview mirror, and Jensen brand stereo with multi-band equalizer. By 1996 the option list grew to include heated seats. Standard was the 4.0, with the 5.2 V8 (and 5.9 in 1998) being optional. As with other models. Package groups with the various trim levels included: fog lamps, skid plates, as well as convenience, lighting, luxury, power, security, and trailer towing packages.

When it was first introduced in April 1992 as an early 1993 model year vehicle, the Grand Cherokee only had one powertrain choice: the 4.0 L AMC-derived straight-six engine that made 190 horsepower. This became the "volume" engine for the Grand Cherokee. Transmission choices included a four-speed automatic transmission (early production ZJs used the AW4 – the A500SE (later 42RE) replaced the AW4 during the latter half of the 1993 model year) or an Aisin AX15 manual transmission. Low demand for the manual transmission resulted in its discontinuation after 1994, but European-market ZJs retained it when coupled to the diesel engine (which was unavailable in North America). The drive train choices included rear-wheel drive or four-wheel-drive. In 1995, the engine dropped 5 horsepower to 185 due to new EPA regulations imposed on the 1996 model year.

In 1998, a variant of the top-level Grand Cherokee Limited, the "5.9 Limited" was introduced. Jeep ads claimed it to be the "world's fastest sport utility vehicle", verified by third-party testing. The primary improvements in the 5.9 Limited version included a 245-horsepower 5.9L OHV V8 engine, heavy-duty 46RE automatic transmission, functional heat-extracting hood louvers, unique wide-slot body-colored grille with mesh inserts, special rocker moldings, low-restriction exhaust with three-inch chrome tip, a low-profile roof rack, and special 16" Ultra-Star wheels. The 5.9 Limited also received a 150 amp alternator and a 2-speed electric cooling fan. Other features include a standard 180-watt, 10-speaker Infinity Gold sound system with rear roof-mounted sound bar, standard sunroof, and an interior swaddled with unique "calf's nap" soft leather and faux wood trim. The 5.9 Limited was awarded "4x4 of the Year" for 1998 by Petersen's 4-Wheel & Off-Road magazine. Production of this model was 14,286 units.

Export models produced at the plant in Graz, Austria, were given the vehicle designation of "ZG".

Second generation (WJ; 1999–2004)

The redesigned WJ 1999 Grand Cherokee shared just 127 parts with its predecessor (mostly fasteners). The European model was coded WG. The spare tire was relocated from the side of the cargo compartment to under the floor. (Like the 1998 ZJ, the rear tailgate glass opened separately.) The two heavy pushrod V8 engines were replaced by Chrysler's then-new PowerTech. The new V8 engine produced less torque than the old pushrods, but was lighter, offered better fuel economy, and provided similar on road performance figures (the 23-gallon fuel tank was replaced with one of a 20.5-gallon capacity). The straight-six engine was also updated in 1999. A redesign of the intake manifold added 10 horsepower (7.5 kW). While other Jeep vehicles used the Mopar 5 x 4.5 bolt circle, this was the first Jeep following the 1987 Chrysler buyout to receive a wider bolt pattern: – 5 x 5.

A notable feature available in this generation was the automatic four wheel drive option called Quadra-Drive, which employed the New Venture Gear NV247 transfer case. This two-speed chain-driven transfer case uses a gerotor, a clutch pack coupled to a hydraulic pump, to transfer torque between the front and rear axles. The transfer case contains three modes, 4-All Time, Neutral, and 4-Lo. In 4-All Time, 100% of torque is sent to the rear axle in normal conditions. If the rear axle starts spinning at a higher rate than the front axle, hydraulic pressure builds up in the gerotor and causes the clutch pack to progressively transfer torque to the front axle until both axles return to the same speed. Neutral mode is intended for towing the vehicle. In 4-Lo, the front and rear axles are locked together through a 2.72 reduction gear ratio. The NV247 transfer case is mated to front and rear axles containing Jeep's Vari-Lok differentials. Vari-Lok differentials also use a gerotor to transfer torque between the wheels on either side of the axle. The major advantage of Quadra-Drive was that the combined transfer case and progressive locking differentials in each axle could automatically control traction between all four wheels. However, only the center differential could be permanently locked, and only in 4Lo. The Quadra-Trac II system included the NV247 transfer case with the standard open front and rear differentials.

The 45RFE and 545RFE automatic transmission in the WJ was notable. It included three planetary gear sets rather than the two normally used in a four-speed automatic. This gave it six theoretical speeds, and it would have been the first six-speed transmission ever produced in volume, but it was programmed to only use five of these ratios. Four were used for upshifts, with a different second gear for downshifts. Although five of the six ratios were used, Chrysler decided to call it a "4-speed automatic". In 2001, the programming was changed to make use of all six ratios. Rather than have six forward gears, the transmission was programmed to act as a five-speed with the alternate second gear for downshifts. The rpm at 70 miles per hour (110 km/h) on a 545RFE is 2000 rpm, 200 rpm less than the 45RFE programming. 1999 and 2000 model year WJ owners can have their 45RFE transmission's programming flashed to enable the extra gear as both transmissions are physically the same. (Must purchase new PCM and ABS module and program them with a fake VIN to make this work.) The 42RE 4-speed automatic remained the transmission for the Inline 6 engine. It had slight changes from the previous model Grand Cherokee.

The interior was also completely redesigned in 1999. The redesign allowed for larger rear doors, and more space for rear passengers. Controls for various items like headlights, heated seats, and rear wiper were moved to more convenient locations. The electronic Vehicle Information center was moved from below the radio to above the windshield, and was standard on all 2000 and up models. Limited models included automatic dual-zone climate control. A 10 CD-Changer was also available with the Infinity Audio package.

In addition to Jeep's UniFrame construction, Daimler Chrysler partnered with Porsche to further strengthen the frame. This was done to reduce NVH. UniFrame is an unusual construction scheme, it 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. All Jeep Grand Cherokees feature UniFrame construction.

The Grand Cherokee received a minor facelift for 2004 including round fog lamps, a lower front fascia and a new body-color matched inset grille design.

Export models produced at the plant in Graz, Austria, were given the vehicle designation of "WG".

Third generation (WK; 2005–2010)

The all-new WK Grand Cherokee debuted in 2004 for the 2005 model year. It was first unveiled at the 2004 New York International Auto Show. Features available for the first time in a Jeep included Quadra-Drive II four-wheel drive, rear-seat DVD player and optional 5.7 L Hemi V8. The 3.7 L V6 engine replaced the 4.0 L Straight-6. A Mercedes Benz sourced 3.0 V6 Common Rail Diesel (CRD) was available outside of North America from launch.

The design still emphasizes power and luxury, with significant work done on improving noise, vibration, and harshness (NVH). However, for the first time, Jeep also emphasized on-road performance to a similar extent as the cornerstone of its brand, off-road capability.

This newfound emphasis on on-road refinement led Jeep to replace the XJ-era live-axle with leading-arms front suspension (found in the ZJ and WJ) with a new design: an independent double-wishbone setup like that which debuted in the 2002 Liberty. The new Jeep changed its philosophy due to what it perceived as increasing demand in the SUV marketplace for on-road performance and decreasing demand for off-road capability. Although classed as a truck-based SUV, the WH/WK Grand Cherokee has more luxuries than a "crossover" especially refinement, capability and NVH.

The 2007 Jeep Grand Cherokee made its European debut at the Euro Camp Jeep held in Ardèche, France. This Jeep has gained 5 stars in the Euro Ncap crash safety tests conducted in 2005.

The Grand Cherokee received a minor facelift for 2008. The bottom part of the headlights became rounded and High Intensity Discharge (HID) Headlamps with auto leveling were added. The lower portion of the front bumper was still removable as it was from launch to increase the approach angle for off-road use. The 4.7 L was refined, now producing 305 hp (227 kW; 309 PS), and 334 lb·ft (453 N·m).

The 2009 Jeep Grand Cherokee is available with an improved 5.7 L Hemi engine rated at 357 hp (266 kW; 362 PS) and 389 lb·ft (527 N·m) of torque. The engine uses variable valve timing to increase fuel economy.

Fourth generation (WK2; 2011–present)

The fourth-generation Jeep Grand Cherokee went on sale in summer 2010 as a 2011 model. It was unveiled at the 2009 New York Auto Show. During development of the WK2 Grand Cherokee, it was used as one of the examples of future products by Chrysler management at the time to convince United States federal regulators in 2009 of Chrysler's future viability in requesting a federal loan, which culminated in the Chrysler Chapter 11 reorganization that same year.

The fourth-generation Grand Cherokee retains its classic Jeep styling combined with a modern and sleek body style. The interior features leather trim and real wood accents, plus Bluetooth and uConnect electronics options. The 2011 Grand Cherokee has won 30 awards for off-road capability, luxury, value, best-in-class, and safety, making it the most awarded SUV ever. Among the awards are: Top Safety Pick for 2011 from the IIHS, listed as a Consumers Digest Best Buy for 2011, Safest SUV in America by MSN Autos, and Truck of the Year for 2011 by The Detroit News.

Like the previous generations, the chassis is a steel unibody. Unlike previous models, the new WK2 features four-wheel independent suspension for better on-road handling. The Grand Cherokee (with the 2011 Durango) WK2 platform uses a Chrysler designed and engineered platform/chassis that Mercedes-Benz later used for the Mercedes-Benz's W166 series. The Chrysler-designed platform/chassis was part of the DaimerChrysler engineering projects that was to launch the new Grand Cherokee with the Mercedes-Benz ML to follow. However, due to the subsequent sale and bankruptcy of Chrysler, the Grand Cherokee launch was delayed and the Mercedes ML launched before the WK2 Grand Cherokee.

Four wheel drive systems include Quadra-Trac I, Quadra-Trac II, and Quadra-Drive II. Using Selec-Terrain, the driver can select modes for Auto, Sport, Snow, Sand/Mud, and Rock.

Optional Quadra-Lift height adjustable air suspension can raise the vehicle's ground clearance up to 11.1 in (282 mm). Lift modes include Park, Aero, Normal Ride Height, Off-Road 1, and Off-Road 2.

Engine choices include the all new 3.6 L Pentastar V6 and 5.7 L Hemi V8. The Hemi V8 retains the Multiple Displacement System (MDS) that shuts down four cylinders in low-power driving situations. The V8 comes with the multi-speed automatic transmission that includes Electronic Range Selection (ERS) to manually limit the high gear operating range. Trailer towing is rated 7,400 lb (3,400 kg) for Hemi models and 5,000 lb (2,300 kg) for Pentastar models. A 3.0 L turbocharged diesel V6 developed and built by Fiat Powertrain Technologies and VM Motori (with Multijet II injection) rated at 177 kW (241 PS; 237 hp) and 550 N·m (410 lb·ft) of torque offered in export markets from mid-2011. The new 3.0 L CRD turbodiesel engine is available in European markets as 140 kW (190 PS; 188 hp) low-power version.

The new Grand Cherokee SRT8, which started production on July 16, 2011, is equipped with a 470 hp (350 kW; 480 PS) 6.4 L Hemi V8 engine. Jeep claims the new SRT8 gets 13 percent better fuel economy than its predecessor. To keep the gas mileage respectable, Jeep has employed a new active exhaust system that lets Chrysler's cylinder-deactivating Fuel Saver Technology operate over a wider rpm band. Chrysler claims that with the larger gas tank, the SUV can now travel up to 500 miles (800 km) on a single tank, while other sources estimate range to be 450 miles (720 km).

Recalls

In 2010, the National Highway Traffic Safety Administration (NHTSA) launched an investigation into 1993–2004 model year Jeep Grand Cherokees which involves the fuel tanks of these SUVs. Because the gas tanks are mounted between the bumper and rear axle, a rear collision could cause the fuel tank to leak, causing a fire. The NHTSA claims that it has reports of 157 deaths resulting from fires caused by Grand Cherokees crashing. Also affected are 2002–2007 Jeep Liberty models and 1986–2001 Jeep Cherokee models, which totals about 5.1 million affected vehicles.

In June, 2013, Chrysler Corporation responded to the recall, agreeing to recall 2.7 million Jeeps, though eliminating both the 1986–2001 Jeep Cherokee XJ and 1999–2004 Jeep Grand Cherokee WJ from the recall. The recall will include 2.7 million 1993–1998 Jeep Grand Cherokee ZJ and 2002–2007 Jeep Liberty KJ vehicles.

Two weeks prior to this recall, Chrysler Corporation claimed that the affected Jeep vehicles were safe, though agreed to recall the affected vehicles later.

To remedy the problem, Jeep dealerships will install a trailer hitch onto the rear bumpers of Jeep vehicles that will protect the fuel tank if the vehicle is involved in a rear impact. If an affected vehicle is not currently equipped with a trailer hitch, one will be installed onto it, and older Jeep and non-factory aftermarket trailer hitches will be replaced with one from Chrysler Corporation. Despite the recall, the market for these Jeep vehicles has not suffered.

In April 2016, the National Highway Traffic Safety Administration (NHTSA) ordered a recall of 2014 and 2015 Jeep Grand Cherokees and other cars that use an electronic gear shifter because it sometimes does not go into (or does not remain in) the park position, despite the operator's best intentions. Consumers reported that they put the car in park and left the engine running, and then were surprised when the car rolled away under power.

An investigation by FCA US and the National Highway Traffic Safety Administration found some drivers have exited their vehicles without first selecting “PARK.” Such behavior may pose a safety risk if a vehicle’s engine is still running. The Company is aware of 41 injuries that are potentially related. The vehicles involved in these events were inspected and no evidence of equipment failure was found. The vehicles also deliver warning chimes and alert messages if their driver-side doors are opened while their engines are still running and “PARK” is not engaged. However, investigation suggested these measures may be insufficient to deter some drivers from exiting their vehicles without selecting “PARK,” so FCA US will enhance the warnings and transmission-shift strategy on these vehicles. The enhancements will combine warnings with a transmission-shift strategy to automatically prevent a vehicle from moving, under certain circumstances, even if the driver fails to select “PARK.”

Jeep has now replaced the shifter with a conventional lever which stays in position for late 2016 models.