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First Drive: 2011 Chevy Silverado HD & GMC Sierra HD

Posted in Project Vehicles on November 1, 2010 Comment (0)
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Photographers: Courtesy of GM

Early in the trip back from the media preview of GM's new heavy-duty pickup trucks, I found myself comfortably seated in a leather chair checking email on my laptop. Not from an airport lounge, but in the back seat of a Wi-Fi-equipped Sierra Denali HD as it rolled down I-70 toward the Baltimore airport.

It wasn't all that long ago when a heavy-duty work truck was just a four-wheeled tool, all grunt and purpose, fitted with nothing more than what was necessary to get the job done. If your tool's powertrain was diesel, you put up with a noisy, smelly, smoky engine in exchange for the torque and longevity it delivered. Those days are gone. We sampled just about every powertrain and cab configuration GM has to offer in its '11 3/4- and 1-ton pickup trucks, and the only one that even came close to that old work truck stereotype was, well, a 1-ton chassis-cab Work Truck model with rubber floor mats and crank windows. Yet even that was a comfortable, quiet rig to drive, with just a hint of the rough ride that characterized unloaded 1-tons not so long ago.

GM isn't alone in this trend of gentrification. All of the Detroit Three have engineered heavy-duty trucks with plush amenities and improved ride quality, then mated them to smooth and efficient drivetrains that deliver remarkable power. (Peak torque from the new Duramax is 765 lb-ft; Ford's new Power Stroke isn't far behind at 735.) None of these work trucks is a penalty box anymore. But GM has inched the bar just that much higher than Ford or Dodge-sorry, Ram-to claim "best in class" in the measures that matter.

The '11 6.6L Duramax diesel V-8 not only produces more power and torque, but it's more efficient too, improving highway mileage up to 11 percent, says GM. Be prepared to pay $8,395 for the Duramax/Allison transmission option. They are listed separately on the sticker (Duramax, $7,195; Allison, $1,200), but you can't get one without the other.

Like that Duramax torque spec, the GM diesel's horsepower is tops too: 397 versus 390 from the Power Stroke and 350 from the Ram's Cummins. GM's max conventional (2WD) tow rating of 17,000 pounds beats Ford's 16,000 and Ram's 12,000. Likewise the Silverado/Sierra's (2WD) fifth-wheel tow rating and payload, in both 3500 and 2500 versions, are all better than the competition.

We're planning a three-way HD truck shootout, similar to the one we did back in May '08, to see if GM's HD pickup truly is better than the rest in a head-to-head, 4WD-oriented comparison. For now, though, let's run down the key elements of the General's newest heavy-duties.

Although the Chevys and GMCs have fresh looks on the outside, the real news is beneath the skin. The HDs now ride on fully boxed frames that are five times stiffer torsionally than previous versions. Front axle weight ratings have gone up by 25 percent, so all 4x4 versions can accommodate snow plows. GM has developed five torsion bar rates to support the different front axle weight ratings, rather than relying on one bar as was done before. In back, the leaf springs are asymmetrical-the front and rear halves aren't the same length-to improve traction and decrease axle hop. The brakes are bigger all around, but so are the bolt circles, meaning '10 and earlier wheels won't fit these trucks and vice versa.

The frames under GM's HD trucks are now fully boxed. There are more crossmembers between the main rails, and now all crossmembers are welded in place. (Previously some were bolted or riveted.) Larger engine and transmission mounts help control unwanted drivetrain vibration, while hydraulic body mounts under extended- and crew-cab bodies isolate them from road irregularities.

During our preview in western Maryland we drove 2500 and 3500 pickups loaded and unloaded, and the ride quality was excellent across the board. Granted, the roads were pretty smooth in this part of the state, and we were never off the pavement. Even so, the trucks' ride and handling rivaled that of their light-duty brothers. You could easily drive one of these trucks cross-country without a bit of harsh-ride fatigue.

And then there's the power. GM brought several trailers to the preview so we could test the new Duramax's capability, and when we towed a 9,000-pound travel trailer, our 2500 4x4 handled the load without breaking a sweat, and without a bit of combustion rattle or black exhaust smoke.

GM's engineers also brought a Power Stroke-equipped '11 Super Duty F-250 SuperCrew for back-to-back comparisons. Our initial seat-of-the-pants impression was that there wasn't much difference between the two in terms of power delivery and ability to tow the 41/2-ton trailers. But then the GM guys instigated a couple of impromptu towing drag races, with the Silverado and Super Duty sprinting side-by-side to the top of a hill. The Chevy always got the hole shot and was first to the top, lopsided victories that make the Duramax's power advantage seem even bigger than it is on paper.

GM also offers the Vortec 6.0L V-8 in its new HD pickups. The gas engine has a new cam profile for better low-end torque production, and the 6L90 six-speed automatic behind it has been strengthened with equipment that includes a new output shaft and four new attachment bosses to the transfer case adapter.

The difference between the two became even more pronounced as we headed down that hill. GM has developed an (optional) exhaust brake system that uses the variable-geometry vanes in the single turbocharger to create exhaust backpressure. With cruise control engaged, the exhaust brake and the cruise control maintain the desired speed. When not in cruise, the Allison transmission and the exhaust brake work together to keep downhill speeds in check. We found that a light tap on the brake pedal was all it took to engage the GM's brake, while in the Ford it sometimes took two or three pushes on the pedal. And when exhaust braking did start, it wasn't as nicely matched with the truck's downshifts as was the case with the Allison.

But really, the fact that we're talking about exhaust brakes at all takes us back to our original point: All of these trucks, regardless of make, are well-equipped to handle just about any chore you want to throw at them, while offering interior appointments and comfort unheard of in this category just a few years ago. But until we undertake that three-way comparo, we have to acknowledge that GM's HD offerings, at least on paper, are head of the class.

There's not much in here that screams "work truck," is there? The heavy-duty GM pickups are just as well-appointed inside as their light-duty brothers. We like that GM's trucks are fully instrumented and offer high-end options like navigation systems. We don't like having to hunt around on the instrument panel for things like 4WD engagement. In one truck we drove, the heater and A/C control was blocked by the transmission lever when it was in Drive. Ergonomically, these trucks still need some help.

Tech Specs
2011 Chevrolet Silverado HD & GMC Sierra HD
Drivetrain

  • Available engines: Vortec 6.0L V-8, 360hp and 380 lb-ft.; Duramax 6.6L diesel V-8, 397 hp and 765 lb-ft.
  • Available Transmissions: Hydra-Matic (6L90) 6-speed auto (w/ Vortec), Allison 1000 6-speed auto (w/ Duramax)

Chassis

  • Front Suspension: Long-short-arm independent w/ torsion bar
  • Rear Suspension: Semielliptical 2-stage multileaf spring
  • Brakes: 4-wheel disc w/ ABS
  • Min. Ground Clearance: 8.2 in (2500 4WD crew cab)

Capacities
2500 Series

  • Max. Payload, 4WD: 3,580 lb (gas reg. cab long-bed)
  • Max. Conventional Towing, 4WD: 13,000 lb (diesel & gas, all configs)
  • Max. 5th-Wheel Towing, 4WD: 17,500 lb (diesel reg. cab long-bed)
3500 Series
  • Max. Payload, 4WD: 6,308 lb (gas reg. cab long-bed dualie)
  • Max. Conventional Towing, 4WD: 17,000 lb (diesel reg. or ext. cab dualie)
  • Max. 5th-Wheel Towing, 4WD: 21,700 lb (diesel reg. cab long-bed dualie)

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