1999-2004 Grand Cherokee (WJ)
Grand Cherokee did not suddenly land in its prestigious position at the top of the legendary Jeep Brand lineup. Its concept has long been in the works, and its design is continuously being refined. The idea to blend the cargo capacity and off-road abilities of a truck with the seating arrangement and comfort of a
sedan began long ago, with vehicles like the Willys All-Steel Station Wagon. Over 60 years of design and engineering experience later, Grand Cherokee achieves
the perfect balance of legendary Jeep Brand off-road capability with interior versatility and the ultimate in luxurious appointments. For 2002, the new Grand Cherokee Overland takes these attributes to a whole new level with innovations such as a High-Output 4.7L Power Tech V8 engine and rain-sensitive automatic windshield wipers. Inside, the steering wheel and interior trim are accented with real Redwood Burl while exclusive suede and leather trim covers the seats. Overland’s interior is so refined, you may start inventing destinations just to enjoy it a bit longer.
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 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 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.