By this time next year, four different GL SUVs will be rolling behind Mercedes-Benz three-star logos. The last to arrive--early in calendar-year 2013--will be an ultra-powerful, first-ever AMG-tuned GL63. With 550 horsepower, it's predicted to be good for a 0-60 mph time of 4.9 seconds.
For now, the GL will rely on a trio of drivetrains, all of which have some major updates from the prior version. The base version, in terms of pricing, is the GL 350 BlueTEC, the turbodiesel edition that gets the best fuel economy of the entire lineup. The 3.0-liter turbodiesel is rated at just 240 horsepower, but brutish diesel torque of 455 pound-feet twists its way through the GL's standard paddle-shifted seven-speed automatic and all-wheel-drive system for a 0-60 mph time estimated at 8.3 seconds. There's some turbo lag, and the diesel's powerband is pretty narrow, and try as we could on our drive through scenic New Mexico, we couldn't press it harder than 110 mph. But the diesel's fuel economy is estimated as high as 24 mpg highway--one of the reasons the smooth, strong powerplant still makes this version one of our favorite big SUVs of all.
There's a twin-turbo, 4.7-liter V-8 in both of the other GLs on offer. They're closely related, and both have features like direct injection that are supposed to help in the quest for better gas mileage. The GL 450's version of this engine makes 362 hp and 406 lb-ft for truly quick 0-60 mph times of about 6.2 seconds. The GL 550? It's even stronger, with an updated version of the same engine making 429 hp and 516 lb-ft, pushing the SUV to 60 mph in 5.5 seconds. Both are a little more gruff than the creamy Benz V-8s of even the recent past, but that's said to be the trade-off for more efficient power. As you can guess, highway gas mileage drops into the high teens on both of these powerful family wagons, though they're marginally better than in the first-generation GL.
The GL utes are some of the most composed full-size SUVs on the market, and the new electric power steering and optional active anti-roll bars don't change that. The steering feel on versions with smaller wheels and tires--19-inchers and under--doesn't feel so loose or light as it could, but it's not overrun with feedback. The variable-ratio rack has different response at low speeds than it does at high ones; the transition's much less obvious here than in some of Mercedes' smaller, lighter cars.
Better at isolating road surfaces than the GM utes (and far better than Ford's Expedition and Navigator), the GL has an independent suspension and standard air springs that are tuned for a pillowy ride; optional active dampers have Sport and Comfort modes that widen the spread, making the highway ride a touch softer while firming up the ride and steering a moderate amount. One thing there's much less of: the side-to-side head pitch we've noticed in the past in almost all Mercedes SUVs. There's also an optional semi-active system with anti-roll bars that can firm up as the GL leans into corners; it's expensive, and it counters some natural body motion that some drivers will expect to encounter, and will rely on as they press the GL into tighter curves. We prefer the more basic setup, and can do without the biggest wheel-and-tire combinations that set up some jiggle in the GL's ride.
For off-roaders there's a package that add a low range, a locking center differential, tuned traction and stability control, and adjustable ride height that lifts the GL from 8.5 inches of ground clearance to a full foot. The trio of GL utes can tow up to 7,500 pounds, too.