Redesigning a vehicle like the Jeep Grand Cherokee is a blessing and a curse. It's a competent vehicle that needs some updates to remain competitive in the market--but it can be tricky to mess with the brand's best-seller (its sales are triple those of the Wrangler) without affecting what people love about the current model. (This doesn't take into account the die-hard off-roaders who cringe every time Jeep announces any changes.) The good news: Jeep met the challenge, managing to make nearly everyone happy.

The five-seat sport/utility comes in two- or four-wheel drive, with three 4WD choices. Quadra-Trac I provides full-time 4WD and is the closest to all-wheel drive of the bunch. It has an NV140 single-speed transfer case and works with a Brake Traction Control System for all-season capability. Quadra-Trac II provides the next level of off-road readiness, combining an active transfer case--the same one found in Quadra-Drive II--with BTCS. This system also uses Throttle Anticipate, which measures throttle movement to maximize traction before any tire starts to slip.

The ultimate 4WD system, however, is Quadra-Drive II. Its NV245 full-time transfer case works with Electronic Limited Slip Differentials (ELSD) in the front and rear that use electronically controlled clutch packs to control and instantly direct power to each axle as needed. The NV245 contains a center differential and its own electronically controlled clutch pack, which makes the 'case capable of everything from completely open to fully locked, with infinite possibilities in between. Quadra-Drive II includes Neutral, for use when being towed. While the limited-slips are designed for off-road use, they also work automatically in daily driving--the ELSD release the clutch packs in front to prevent crow hop and allow the wheels to rotate at different speeds in turns. Quadra-Drive II-equipped Jeeps use an electric T-handle lever to switch between 4-Hi and 4-Lo.

For 2005, the Grand also receives all-new suspension systems in the front and rear. Replacing the live-axle Quadra-Link setup in front is a short- and long-arm independent suspension. The rear continues to use a live axle, now with tubular control arms and a track bar. Worried that IFS will ruin the Grand Cherokee's off-roadability? According to Jeep, front suspension travel is 10 percent better than it was in the 2004 model. The new front layout provides the typical advantages of IFS: a lower center of gravity, 100 pounds less unsprung mass, and a more comfortable ride.