Spied: 2010 Chevrolet Silverado Heavy Duty
By: Mike Levine Posted: 06-30-08 09:00 PT
© 2008 PickupTrucks.com, , Brian Williams for Brenda Priddy & Co.

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Update #1: 06-30-08 20:09 PT

We'll throw some more diesel on the speculative fire. A reliable source called today, saying GM is targeting well over 700 pounds-feet of torque for the 2010 Duramax. Is 750 the new 660? Stay tuned.

Even with truck sales way down and fuel prices way up, General Motors' heavy-duty pickups have to keep up with changing federal regulations and the competition. Here are the first pictures of a 2010 Chevrolet Silverado 2500 Duramax diesel test mule.

The Silverado HD (and its twin, the GMC Sierra HD) first went on sale about 18 months ago but GM is giving the truck a mild facelift that hints at major revisions happening under the hood.

The grille in these photos is temporary, cribbed from a current light-duty Chevrolet Silverado 1500, but the revised front bumper is meant to be a production version. GM has softened the huge metal flares at the corners of the current Silverado HD's bumper by topping off the uppermost portion with plastic from end to end for 2010.

The inlet in the middle of the front bumper feeds air to the truck's transmission oil cooler. It's about a third larger than the current inlet, which makes us wonder about the changes GM has in mind for the Silverado's Allison transmission.

The Allison gearbox is mated to a 6.6-liter Duramax diesel engine, which will be overhauled to meet tough new EPA rules for nitrogen oxide emissions that go into effect Jan. 1, 2010. The bigger inlet could mean a next-generation Duramax engine that requires extra air for a new exhaust gas recirculation system, which reduces NOx, but GM has already stated that the 2010’s NOx emissions would be scrubbed using urea selective catalytic reduction, which should require a less complex EGR system.

Maybe it's just the heat, but we’re wondering if GM and Allison are planning to add extra gears to the current six-speed Silverado for improved fuel economy and towing efficiency. Could the Allison transmission get eight cogs, like some recent luxury cars, or will it make the leap to 12, like some big rigs use? Twelve gears isn't as hard to attain as some might think; a gear splitter can be added between the back of the transmission and the driveshaft or transfer case, depending whether the truck is two- or four-wheel drive. The bottom line, though, is that extra gears would likely require improved airflow to the transmission oil cooler, and thus a bigger inlet in the front bumper.

Extra gears could also allow the Silverado to one-up new heavy-duty pickups from Dodge and Ford, expected to arrive by 2010 and 2011, respectively. The 2011 Ford Super Duty will feature a new 6.7-liter Scorpion V-8 diesel engine and six-speed transmission.