GM has stated that it will be rolling out the full lineup of Silverados and Sierras early next year, and judging by this spy shot of what looks to be a production-intent Sierra 2500HD, fans of heavy hauling indeed will not have to wait long.
What we see is of little surprise - the sheetmetal appears to be largely carried-over from its half-ton brethren, but we wouldn't be shocked if there's another inch or two of hood budge hiding underneath the camo. The interior will also be brought over from the 1500 lineup. The independent front suspension remains, although we'd expect it to employ somewhat more massive components than the lighter-duty version. What we don't see yet is whether GM will use its new coil-over spring and rack-and-pinion steering architecture, or if the new HDs will continue to use torsion bars and a recirculating-ball steering box.
Don't expect much in the way of powertrain changes at the top of the lineup, as the Duramax already possesses class-leading horsepower (360 hp) and torque (650 ft-lbs.), and the existing six-speed Allison transmission does a great job harnessing that power. The 6.0L LY6 version of GM's GenIV pushrod V8 with approximately 350 hp and 380 ft-lbs. of torque will most likely be the base engine, and will be backed by the 6L90E heavy-duty version of GM's new corporate automatic transmission. A twin-turbo variant of the Duramax is rumored to be coming by the end of the decade for those who are not yet confident that they can tow their house around the block.
UPDATE: The folks at Cheers & Gears have some shots of the GM HD pickups in the open from this week's official introduction.
[Source: Popular Mechanics, GM]