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June 2010 Drivelines

GMs Heavy Duty Pickup Truck
Drew Hardin
| Contributor
Posted June 1, 2010

GM Unveils New HD Pickups

GM Unveils New HD Pickups
If you're interested in GM's new heavy-duty pickup trucks, you want to know how they work. So we'll skip over the new sheetmetal, the Wi-Fi connectivity, and the rear doors that open wider than ever to get to the juicy stuff. Oh, wait. We can't.

GM has apparently taken a page out of Ford's playbook and released information about an all-new turbodiesel without providing output numbers, saying only that the new 6.6L Duramax has "significantly more torque and higher horsepower ratings." Is GM waiting for Ford to announce its new Power Stroke numbers, or vice versa? Is this some game of turbodiesel chicken?

What we do know is the new Duramax has an exhaust brake system, which uses the turbine control of the variable geometry turbocharger and the compression of the engine to generate backpressure. Backing the 'max is a new Allison 1000 six-speed automatic transmission, which has been strengthened to handle the higher torque loads while also sending more of the engine's power to the wheels, reducing what GM calls "spin loss." The new turbodiesel and its tranny will improve highway fuel economy by up to 11 percent and boost tow ratings. Properly equipped, a 4WD 3500HD diesel dualie will be rated to tow 19,600 pounds with a fifth-wheel hitch.

There have been improvements to the HD's gasoline powertrain too, with the 6.0L V-8 getting a new camshaft profile for "more torque lower in the rpm band." GM didn't release power ratings for this engine either.

The new trucks retain an independent/torsion bar front suspension, though it has been redesigned to offer up to a 25 percent greater front axle weight rating so a snow plow can be used on all 4WD cab configurations fitted with the plow package. Out back are asymmetrical leaf springs to minimize axle hop.

GM's HD pickups will go on sale this summer. We'll bring you the power specs on the new engines just as soon as GM and Ford quit their staring contest. Maybe it's time for a giant tow rig rematch.

King of the hammers winner!
Loren Healy is the new King of the Hammers! After 135 miles of desert racing and rockcrawling the Farmington, New Mexico, native eeked out a win with a 28-second lead over Brad Lovell. Loren was piloting a Jimmy's 4x4 ( and not only won the race, but qualified for it just days prior by entering the Last Chance Qualifiers of the Griffin Radiator King of the Hammers. Tune in next month for the full coverage or visit

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