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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's Ultium EV platform finally shows up in Q3 sales numbers

General Motors has heralded its Ultium battery-electric platform as the future of its passenger car and truck lineup, but for the first two years of its existence, its impact on the marketplace has been virtually nonexistent. Well, that finally changed in the third quarter of 2023, and while the cars based on this architecture don't represent anywhere near the volume of GM's broader combustion portfolio, we're reaching a point where Ultium products are finally in view (and in the hands) of real-world shoppers. At this point, five U.S.-market Ultium models are in production: the GMC Hummer EV, Cadillac Lyriq, Chevrolet Blazer & Silverado EV, and BrightDrop Zevo 600. If you're not familiar with that last one, that's OK; it's a commercial product that you likely won't see on the road for some time. Together, these four combined for 4,257 sales in the third quarter alone — up from 2,663 for the entire first half of the year. While that may not seem like a significant uptick when viewed from altitude, the quarter-to-quarter numbers paint a clearer picture.  Let's toss out the stragglers first. The Chevy Blazer EV, and Silverado EV for example, are barely in production. GM delivered 19 Blazers and 18 Silverados in the third quarter and that's the entirety of their production runs so far. Likewise, GM's BrightDrop Zevo 600 delivery van effectively exists apart from the consumer marketplace, so its contribution of just 35 units can be set aside too. That leaves us the two you've heard of: the GMC Hummer EV and Cadillac Lyriq — models with high sticker prices and long reservation queues.  Through the second quarter (remember, we're talking six months here), GMC sold 49 Hummer EVs. No typo. In the three months that made up the third quarter, GM moved 1,167 of them. Not only is that a dramatic improvement over the first half, but it's more Hummers than GMC sold in the entirety of 2022 (854). Lyriq's improvement was less eye-popping on paper, but after moving just 122 total units in 2022 and 2,013 of them in the first half of 2023, Cadillac managed to up that figure to 3,018 units in the third quarter alone.  GM is betting its short-term EV future on the Ultium platform, so these trends need to continue if that's going to be a profitable wager.

GM opens official investigation into C8 Corvette transmission leaks

In March 2020, a month after Chevrolet began customer deliveries of the 2020 C8 Corvette, a GM dealer technician created a Reddit thread about a leaking gearbox in a Corvette with 32 miles. That car hadn't even been sold yet. Since then, as a search of "C8 Corvette transmission leak" shows, it's been tales of woe for some owners. Something in the Tremec TR-9080 transaxle in the back of the mid-engined Corvette doesn't work as it should, the fault able to cause codes that the transmission needs service, or that the driver needs to shift to park. In some cases, the battery would die because of follow-on issues after the initial transmission code, that code preventing the car from powering down. As Autoevolution reports, GM filed paperwork with the National Highway Traffic Safety Administration in August to look into what's going on. Between forum threads and GM's investigation document, there are several issues mentioned. The most common appears to be the dual-clutch transmission leaking fluid due to gasket failures like the one suffered by one owner at 858 miles, and another for an owner currently enduring a second leaking transmission. The Midengined Corvette Forum reported that Chevy engineers redesigned the TR-9080 pan, fitting Corvettes with the new unit at some point in the 2021 model year. The original pan was stamped steel unit affixed to the engine with two studs and 13 bolts, plus "reinforcement plates." The updated pan is said to be a cast aluminum unit affixed with two studs and 17 bolts, omits the reinforcement plates, and gets a new machined new groove around its edge to seat the gasket seal. The GM paperwork now at the NHTSA mentions a P1789 code, and says one reason for it could be "debris on the park position sensor magnet causing an incorrect position reading to the TCM." This might be caused by another issue mentioned in forums, which is clogged transmission filters. GM gives instructions for returning transmission filters to the company, and a poster on one forum said the Corvette tech at the dealer where he bought his Corvette told him the automaker "requires every used transmission filter to be returned to GM."  Whatever's going on, the problems haven't stopped, and they go beyond the P1789 code. Over the weekend, a 2022 Corvette owner posted on Corvette Forums that he got a check engine light on his car after just 850 miles.