adminWheel-on Abel Zhakata
The Jeep Grand Cherokee is a mid-size SUV produced by the Jeep division of American manufacturer Chrysler. While some other SUVs were manufactured with body-on-frame construction, the Jeep Grand Cherokee has always used a unibody chassis.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, Adam 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. The Grand Cherokee debuted in grand fashion at the 1992 North American International Auto Show in Detroit, Michigan.
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, Laredo, and Limited. The base model included features such as full instrumentation, cloth interior, 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 and SE, although they were finally included in 1995. 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 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, and cruise control. Exterior features included medium-grey plastic panelling on the lower body and five-spoke aluminium wheels. The Limited was the premium model, featuring lower body panelling that was the same colour as the rest of the vehicle. The Limited also boasted standard features such as leather seating, power sunroof, heated mirrors, heated power seats, and a key-less entry system. The “Up-Country” version was also offered between 1993 and 1997, often painted “Champagne Pearl” or black. It came with 4WD and a 4.0 straight-6. Package groups with the various trim levels included: Convenience, Fog Lamp / Skid Plate, Lighting, Luxury, Power, Security, Trailer/Towing.
When it was first introduced in April 1992 as an early 1993 model year vehicle, the Grand Cherokee only had one power train choice: the 4.0L AMC-derived 4.0L Power Tech I6 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. 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”. 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 louvres, unique wide-slot body-coloured 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 fake wood trim.
The redesigned WJ 1999 Grand Cherokee shared just 127 parts with its predecessor (mostly fasteners). The spare tire was relocated from the side of the cargo compartment to under the floor. The rear tailgate glass opened separately. The two heavy pushrod V8 engines were replaced by Chrysler’s then-new PowerTech. 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 Inline 6 engine was also updated in 1999. A redesign of the intake manifold added 10 horsepower (7.5 kW).
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.
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 centre 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 unitised 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-colour matched inset grille design.
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.
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 new-found 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 WK Grand Cherokee has more luxuries of a crossover especially with NVH.
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 levelling were added and the lower portion of the front bumper became removable 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.
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.
The body design is all new and has undergone testing for aerodynamic efficiency while improving ruggedness with more than 5,400 welds in the body alone. This results in a 146% increase in torsional rigidity compared to the previous design. This improves durability and reduces noise, vibration, and harshness. 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 WK2 platform uses a derivative based on Mercedes-Benz’s W166 series.
Engine choices include the all new 3.6 L Pentastar V6 and 5.7 L Hemi V8. Four wheel drive systems include Quadra-Trac I, Quadra-Trac II, and Quadra-Drive II. Optional Quadra-Lift air suspension can raise 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. Also new is the Selec-Terrain, which has modes for Auto, Sport, Snow, Sand/Mud, and Rock.
The Hemi V8 retains the Multiple Displacement System (MDS) that shuts down four cylinders in low-power driving situations. And the V8 remains coupled with the multi-speed automatic transmission which includes Electronic Range Selection (ERS) to manually limit the high gear operating range. The 3.6 L Pentastar V6 replaces the 3.7 L and 4.7 L PowerTech engines. The 5.7 L Hemi engine was retained as the V8 option, although no Hemi badging is used on the exterior of the vehicle. Also, the WK program code remains.
Some features changed with this generation are the handbrake being replaced by a footbrake, and the wiper stalk on the right side of the steering column being moved to the turn signal stalk, which also means the lights move to the dash.
For the 2011 model year, the Grand Cherokee was offered in five trim levels: Laredo, Laredo X, Limited, Overland, and Overland Summit. The performance SRT-8 version returned for the 2012 model year.[24] Also for 2012 a S-Limited model was offered in Germany.
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