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GM considering new powertrain options for large SUVs

Aside from the new General Motors offerings, there's not a whole lot of action going on in the fullsize SUV segment. That doesn't seem to be stopping GM from pushing the envelope in the market as Automotive News is reporting that the automaker is looking to introduce some new powertrain options into the Chevy Tahoe (and Suburban), GMC Yukon (and Yukon XL) and the Cadillac Escalade - all have been redesigned for the 2015 model year.
Now, we already know that GM and Ford are collaborating on nine- and ten-speed transmissions for a broad range of applications (including the big SUVs), but this new report says that GM is also considering other options as a way to one-up the competition and, of course, to optimize fuel economy. AN quotes Jeff Luke, executive chief engineer for GM trucks, as saying that "interesting powertrain technologies" are coming including a return of a hybrid SUV and possibly even a diesel engine. Although it sounds like the latter could come down to how customers respond to the 2014 Jeep Grand Cherokee EcoDiesel.

GM exploring ways to raise half-ton Duramax diesel tow rating

Lots of truck owners cheered when GM announced fuel economy numbers for the 2020 Chevrolet Silverado with the 3.0-liter Duramax diesel inline-six. Even after Ram let loose its EPA mileage ratings for the 2020 Ram 1500 EcoDiesel, the Chevy oil-burner still took the trophy. The victory was years in the making, GM engineers spending an entire four-year development cycle refining the LM2 Duramax to increase mileage. The tradeoff, as well all know by now, is towing; the Duramax in half-ton duty pulls a maximum 9,300 pounds in the Silverado. Rivals across town can do more, the Ford F-150 PowerStroke rated at 11,500, the Ram 1500 EcoDiesel game to pull 12,560. GM engineer John Barta told Muscle Cars & Trucks that more hauling chops could be on the way, explaining, "We’re actually looking at upgrading some of the materials around (the engine bay) to see if we can maybe raise our tow rating." Engine bay materials are at issue due to thermal complexities underhood. John Barta, GM's assistant chief engineer of diesel engine controls, said the Duramax's inline-six configuration allowed engineers to get emissions hardware like the combined selective catalytic reduction, diesel oxidation catalysts, and diesel particulate filter unit closer to the engine, where it heats up quicker, getting emissions down quicker. But that filter puts another heat source in those confines, enforcing a cap on the tow rating to keep the engine and other systems from overheating. "If you look under the hood," he said, "youÂ’ll see a significant amount of silver ‘moon tapeÂ’ around to make sure things arenÂ’t getting overheatedÂ… if we were to go up in higher towing, which we can, we start impacting the possibility of deteriorating some of the components.” There isn't much space for more grille, so swapping for a better grade of "moon tape" or a different kind of material could reduce engine bay heat, extracting a higher tow rating in the process.  It's important to note a point Barta's been making for months about the Duramax figures, though. "Even though itÂ’s nice to brag about big numbers, in reality, light duty customers are not towing that large with their trucks," and, "We do know that (95 percent) of our light duty customers donÂ’t tow over 9,000 pounds." On our First Drive of the 2020 Silverado diesel we called out the tow rating, but emphasized that the Chevy and GMC have more important challenges to overcome.

2014 Chevy Silverado details continue to dribble out

PickupTrucks.com has gotten its hands on a few more details concerning the 2014 Chevrolet Silverado and the 2014 GMC Sierra. General Motors held a conference call on the two trucks, allowing Jeff Luke, executive chief engineer for both, to answer a few questions. Luke said truck buyers are largely concerned with power and fuel economy, and as such, GM will continue to explore new methods of providing both. That may translate into any number of drivetrain permutations, including light-duty diesel engines, eight-speed transmissions or even a twin-turbocharged V6.
What's more, both the 2014 Silverado and its GMC twin will boast a tow rating of 11,500 pounds, but only when equipped with a max-trailering package. Without that special package, the rating drops to 10,200 lbs for regular cabs and 9,700 lbs for crew cabs. Buyers will no longer be able to opt for a 4.10 gear ratio.
We're also excited to hear that GM plans on making the Z71 package into something more than just a few a stickers. While Luke didn't go into details, PickupTrucks.com says "it will get significant improvements in the future." Head over to the site for a quick rundown of the call's highlights.