Quadra-Trac I is a road-oriented system that yields full-time four-wheel drive, with torque split 48/52-percent front/rear. Quadra-Trac II adds a two-speed transfer case with low range and has a feature called Throttle Anticipate, which works to anticipate slippage and selectively applies the brakes to maximize traction. The most off-road-oriented system is called Quadra-Drive II; it uses a full-time transfer case with electronic limited-slip differentials to detect tire slip and send engine torque to the wheels with traction. It employs an electronically coupled clutch pack, and the front and rear differentials can be varied at each axle to also help maximize traction.
All three models are available with either four-wheel drive or rear-wheel drive. The base Laredo model gets the V6 and Quadra-Trac I if so equipped, though the 4.7L V8 and both other 4WD systems are optional. The Limited steps up to a standard 4.7L V8 and Quadra-Trac II system, plus useful off-road aids such as hill start assist and hill descent control system. The Overland gets the 5.7L V8 and Quadra-Drive II system, plus tow hooks and skid plates on 4WD models. The turbo-diesel engine is optional on Limited and Overland.
Engines on the Grand Cherokee range from a base 210-horsepower, 3.7L V6, to an economical and torquey 3.0L common-rail turbocharged diesel V6 that makes 215 horsepower and 376 lb-ft of torque, to a newly revised 4.7L V8 now making 302 horsepower and 329 lb-ft. At the top of the range is the 5.7L Hemi V8, making 330 horsepower and 375 lb-ft.
The 4.7L V8 makes 30 percent more power and ten percent more torque than last year's 4.7L, while at the same time boasting a five-percent increase in fuel economy. It's also flex-fuel capable, allowing a mix of ethanol and gasoline up to 85-percent ethanol (E85). The Hemi V8 includes Chrysler's multi-displacement system (MDS), which temporarily shuts down four of the cylinders to save fuel when the V8's power is not needed.
All four engines are mated to five-speed automatic transmissions that feature electronic range select shift control for more control when off-roading or trailer-towing, or on curvy roads; the Grand Cherokee has a tow rating of up to 7,400 pounds.
Grand Cherokees get a new short- and long-arm front suspension and five-link rear suspension geometry that's designed to provide good control on the road without compromising off-road articulation.
The interior has been refreshed, with improved materials for 2008, including a redesigned center console, revamped, LED-lit gauge cluster, and upgraded soft-touch instrument panel materials. Door panels have new armrests designed for comfort.
Each of the Grand Cherokee models get different upholstery. Laredo models have standard cloth and optional leather, while Limited models get two-tone perforated leather and the Overland model gets new saddle perforated leather seats with accent piping.
At the top of the range, the Overland model includes a long list of premium features such as HID headlamps, heated seats in the first and second row, the ParkSense parking aid, a navigation system, a roof rack, chrome 18-inch wheels, and Sirius satellite radio. A wealth of options and packages are available, including a rear-seat entertainment system, the MyGig music storage system, and the all-new Sirius Backseat TV.