The Jeep Grand Cherokee (WJ) is the second generation of the Jeep Grand Cherokee sport utility vehicle. Unveiled in Detroit, Michigan, on June 16, 1998, production lasted until 2004 in the US, continuing in foreign markets until 2005. The WJ was completely overhauled from its ZJ predecessor and was renowned for its off-road capability. Jeep marketed the (WJ) as "the most capable SUV ever."
Background Unveiled at Detroit, MI Cobo Hall on June 16, 1998, the redesigned WJ 1999 Grand Cherokee shared just 127 parts with its predecessor (mostly fasteners) and took 28 months to develop from its March 1996 design freeze (styling approval in Q3 1995). The spare tire was relocated from the side of the cargo compartment to under the floor. 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 Inline 6 engine was also updated for MY1999. A redesign of the intake manifold added . 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 wheel bolt pattern: – 5 x 5 - (metric 5 x 127mm).
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 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. 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. The redesign allowed for larger rear doors and more space for rear passengers. Controls for various items like headlights, heated seats, and rear wipers 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 CD-changer with capacity for 10 CDs 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 noise, vibration, and harshness (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 secondary 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", which feature minor differences from the US model, including a relocated radio antenna (moved from front right fender to integrated on rear passenger side window), power folding mirrors, height adjustable headlights, plastic rocker covers on Limited trim models (only available on Laredo trim on US models), as well as leather shift knobs on Overland trim models. Chrysler also claims the vehicle received other improvements to reduce "NVH". "WG" models were also manufactured at the Cordoba plant for the Argentinian market.
New features
The first-generation Jeep Grand Cherokee (ZJ) offered many new and class-exclusive features, and the second-generation Jeep Grand Cherokee WJ continued to offer new features that were not yet available on its competitors, such as the Chevrolet Blazer and Ford Explorer.
At the time of its release, the all-new 1999 Jeep Grand Cherokee WJ had many standard and optional features that were class-exclusive. HomeLink allowed the driver to program up to three devices, such as garage door openers, estate gates, and other controlled access devices, and operate those devices with buttons located in the overhead console. A state-of-the-art automatic dual-zone climate control system used infrared sensors located in the climate control panel to monitor the surface temperature of both driver and front passenger to automatically control the interior temperature for both front passengers. The Jeep Memory System allowed for two drivers to set their individual driver's seat, side mirror, and radio setting by using buttons located on the front driver's door interior panel to recall their preferred settings at the touch of a button, or upon insertion of the corresponding key into the ignition (the keyless entry remotes were color-coded either black or gray, and had either a '1' or '2' on the back of the remote to help the drivers easily identify their remote).
For the 2002 model year, the Grand Cherokee WJ received its first mid-cycle refresh. This included the introduction of three new models: a value-oriented Sport, the Laredo-based Special Edition, and the new range-topping Overland. A new 4.7L High-Output Power Tech V8 gasoline engine became available on Limited models, and was standard on Overland. All models receive new radios, which included a standard A/M-F/M stereo radio with a single-disc CD player on Laredo and Limited, with an A/M-F/M stereo radio with Radio Data System (RDS) and cassette and single-disc CD players standard on Overland and optional on all other models (both radios featured standard CD changer controls for the optional ten-disc remote CD changer in the rear cargo area). For vehicles equipped with the Infinity Gold premium audio system, the 'Infinity Gold' emblem was removed from the front door speaker grilles, and the Laredo no longer featured carpeted front and rear door panels. Also on the interior, all models received a new chrome 'Jeep' steering wheel emblem, as well as new interior accent trim (faux aluminum on Sport, Laredo, and Special Edition, and faux woodgrain on all other models). Sport and Laredo models received new "Landscape"/"Millennium" cloth seat fabric as standard equipment, and Limited models received new "Royale" leather seat trim (the previously available "Royale" leather seat trim remained available on Sport, Laredo, and Special Edition models). A new front grille and headlamps were introduced on Limited models, new tire and wheel combinations were available for all models, and in midyear 2002, a full-color GPS navigation radio with a single-disc CD player and ten-disc remote CD changer became available on Limited and Overland models. All radios supported dealer-installed accessory Sirius Satellite Radio and U Connect hands-free Bluetooth phone system. To round out the changes for 2002, a full-size spare tire and wheel was now standard equipment on all models, front side-impact airbags and power-adjustable foot pedals were available (the Vehicle Identification Number differentiated between frontal airbags only and frontal and front side-impact airbags with the characters '4' and '8' respectively as the third digit) and center roof rack cross rails were now only available as a dealer-installed accessory for all models.
A second exterior facelift was introduced for the 2004 model year, and included revised front grilles and fascias (bumpers) for all models (Laredo models also received newly styled round front fog lamps as an optional feature). The Laredo-based Special Edition model rejoined the lineup, and a new Columbia Edition model (also based on the Laredo) was introduced. The base Laredo model was now only available with the base "E" Package, and included fewer standard features (including the deletion of carpeted front and rear floor mat and rear cargo area tonneau cover). Production of the Grand Cherokee WJ ended in mid-2004, as the all-new third-generation Jeep Grand Cherokee (WK) was introduced, and the Jefferson North Assembly Plant received a retooling for production of the all-new model. All 2004 models equipped with four wheel drive received Jeep's "Trail Rated 4X4" certification, and an emblem on the front left fender.
Yearly changes
1999 - 1999 saw the introduction of the all-new, second-generation Jeep Grand Cherokee WJ. While similar in dimensions and style to the first-generation Jeep Grand Cherokee (ZJ), the WJ Grand Cherokee featured a more modern exterior design and an all-new interior. While the 4.0L "Power-Tech" Inline Six-Cylinder (I6) engine and 42RE four-speed automatic transmission both carried over from the previous-generation model, the previous 5.2L "Magnum" V8 engine was replaced by an all-new 4.7L "Power-Tech" V8 engine, which was mated to the all-new 45RFE four-speed automatic transmission (the 5.9L "Magnum" V8 engine was dropped after the 1998 model year). The spare tire and wheel were relocated from the left side of the rear cargo area to underneath the cargo floor. This decreased on available cargo space, but made it easier to access the spare tire and wheel.
2000 - Having been fully redesigned for the 1999 model year, the 2000 Jeep Grand Cherokee received minimal changes. However, the 4.7L "Power-Tech" V8 engine's 45RFE four-speed automatic transmission was replaced by the 545RFE five-speed automatic transmission. Finally, the base Laredo "D" Package was discontinued, which meant that the Laredo model now included the Electronic Vehicle Information Center (EVIC) with an overhead console as standard equipment.