2008 Gmc Sierra 3500hd Duramax Diesel 4 Wheel Drive Dually Allison Automatic on 2040-cars

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Torque time | 2017 GMC Sierra HD First Drive

It's not the truck that counts, it's how you use it. It's the heavy stuff you fit in its bed or the extremely heavy stuff that gets hooked up to the tow hitch. The ATV, the Jet Skis, the trailer with more square footage than a Greenwich Village apartment. Perhaps you need to get Seabiscuit or, uh, Mr. Ed to wherever they need to gallop next. In our case, there's a pair of very serious-looking snowmobiles perched atop the bed of a GMC Sierra. They spread out as wide as the extended tow mirrors, and their back halves are dangling precariously beyond the truck. Sterling Archer would be giddy; I'm a little nervous. But only because canyon roads and wide vehicles with a high center of gravity go together like peas and custard. The added weight is no sweat at all. That's because this is the 2017 GMC Sierra HD Denali, a truck with the sort of enhanced power, torque, suspension, and stopping capability expected of a heavy-duty pickup. And for this year, the power and torque get a serious bump courtesy of a new 6.6-liter Duramax turbodiesel engine reengineered from almost the ground up with 90 percent new parts. It's quieter and more efficient and it emits less, while most importantly producing 445 horsepower and 910 pound-feet of torque. That's up from 397 and 765, respectively. Chevy fans will note that the same engine is also available in the updated 2017 Silverado HD. Now, for those keeping score at home, that horsepower is best-in-class but the torque number still falls short of the new Ford Super Duty and its Power Stroke diesel V8's 925 lb-ft. Aw shucks. For the record, GM's engineers didn't seem too concerned that they weren't able to eke out an extra 16 torques just to say they're No. 1. "We wanted to first meet emissions and then deliver the maximum horsepower and torque we could, and deliver it over the widest usability range possible," said chief engineer Eric Stanczak. And let's be honest here, 910 pound-feet is herculean, and once again, a jump of 145 lb-ft. Or one Subaru Impreza's worth. Or 110 more than the best Ram can do on a 2500, and its Cummins turbodiesel's 800 pound-feet was eye-popping not too long ago. (The Ram 3500 maxes out at 900 lb-ft with the right transmission.) Ah, but here's the rub. That Cummins-equipped Ram 2500 can still tow more weight according to SAE-compliant measurements – 17,510 pounds for a Ram crew cab with a short bed versus 13,000 in the similar Sierra 2500. The Ford F-250 can manage 15,000.

GM planning to put its fullsize pickups on a big diet, too

General Motors is just coming off a complete redesign of the Chevrolet Silverado and GMC Sierra for 2014, but in the US fullsize truck market, there is no rest for the weary. According to Reuters, plans are already unfurling for both trucks to drop pounds from their curb weight over the next few years, but this will unlikely be able to keep pace with the 700-pound diet targeted for the next-generation Ford F-150, a truck expected to debut late next year.
The biggest weight reduction for these trucks might not be available until the next full redesign, which will likely happen around 2019, but the article says that smaller updates could shave pounds in the meantime. Two examples given include an "aluminum-intensive" version of the Silverado that could shed 250 pounds and debut around the same time as the lighter-weight, aluminum-bodied 2015 Ford, and there is also talk of reducing weight for driveline components such as axles and driveshafts. These changes are all part of an attempt to meet strict new fuel economy standards coming in 2017, targets which will get even tougher in 2025.

2015 Chevy Silverado, GMC Sierra can tow up to 12,000 pounds

Think back to the launch of the 2014 Chevrolet Silverado. At the time, General Motors happily trumpeted that its fullsize pickup could tow up to 11,500 pounds when properly equipped - impressive stuff, no doubt. But now, revised tow rating practices have been put into place, called SAE J2807. And with these new methods of testing, GM can now officially rate both the Silverado and its GMC Sierra twin as being able to tow up to 12,000 pounds.
Of course, not all Silverado and Sierra models are capable of this feat. In fact, because of SAE J2807, most of the truck models have actually had decreases in tow ratings from the 2014 to 2015 model year. For example, a 2014 Silverado Crew Cab with the 5.3-liter V8, 5.7-foot box and 3.73 rear axle was rated at 11,200 pounds in 2014, but has since been reduced to 10,800 in 2015. Same goes for the Sierra.
But for 2015, both the Silverado and Sierra can be had with a more powerful 6.2-liter V8, as well as a Max Trailering Package that includes a 9.76-inch rear axle, heavy-duty rear springs, revised shock tuning, improved cooling and a new trailer brake controller. There are also four- and seven-pin, bumper-mounted connectors, a trailer hitch (duh), and a G80 locking rear differential. This configuration, with either model, is the only way you can actually tow 12,000 pounds.