Midsize SUV sports a variety of engines

The Jeep Grand Cherokee midsize sport utility vehicle gets an update that includes a more powerful 4.7-liter V-8 engine and newly available entertainment options, including a MyGIG navigation and entertainment system and Sirius Backseat TV.

The Grand Cherokee is currently one of the few SUVs with an available diesel engine, but more automakers are expected to introduce diesels for their SUVs in the coming years.

Casual observers probably won't be able to tell the difference between a 2009 Grand Cherokee and earlier models; the differences are pretty subtle. The headlights and grille are new, but their overall appearance hasn't changed much. High-intensity-discharge headlights are newly optional and 18-inch chrome wheels are available.

Modifications to the cabin are modest and center on the dashboard, door panels, and center console. The gauges are new, as are the door armrests and the leather-wrapped parking brake handle. The upscale Overland trim gets a wood steering-wheel rim and perforated leather seats with special piping.

The new Sirius Backseat TV system has a satellite video receiver and two roof antennas and can show three channels: Nickelodeon, Disney Channel, and Cartoon Network.

Shows can be viewed on the rear video screen and on the available MyGIG navigation radio's screen when the SUV is in park. The MyGIG system has a 20-gigabyte hard drive that can store music and photos and can, in conjunction with Sirius Satellite Radio, reroute the Grand Cherokee around traffic problems.

The Grand Cherokee's 3.7-liter V-6, 5.7-liter V-8, 6.1-liter V-8, and 3.0-liter diesel V-6 carry over unchanged from the prior model year, but the 4.7-liter V-8 receives a number of changes, including a higher compression ratio and new induction system; it makes 305 horsepower and 334 pounds-feet of torque.

All engines team with a five-speed automatic transmission. The 6.1-liter makes 420 hp for the SRT8 version.

Rear- and four-wheel-drive versions are offered, and the latter driveline comes standard with hill descent control that's designed to keep the SUV's speed to a crawl when traversing difficult terrain. Hill start assist is also offered and serves to keep the Grand Cherokee from rolling backward on an incline.

All-disc antilock brakes, side curtain airbags, and an electronic stability system are standard.

A rearview camera and rear parking sensors are available.