Jeep Grand Cherokee

The Jeep Grand Cherokee is a mid-size SUV produced by the American manufacturer Jeep. While some other SUVs were manufactured with body-on-frame construction, the Jeep Grand Cherokee has always used a unibody chassis.

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 systems allowed potential conflicts to be resolved faster, thus 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.

Jeep Grand Cherokee (WK)

The all-new third generation Grand Cherokee (WK) was unveiled at the 2004 New York International Auto Show by Jeep for the 2005 model year. New features for Jeep included, Quadra-Drive II four-wheel drive, rear-seat DVD player, and optional 5.7 L Hemi V8 engine. The 3.7 L V6 engine replaced the 4.0 L Straight-6 engine.

The design still emphasized power and luxury, with significant work done on reducing 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 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.

Jeep Grand Cherokee (WJ)

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 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 23-gallon fuel tank was replaced with one of a 20.5-gallon capacity). The Inline 6 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.