When it comes to trucks, bigger is almost always better. It's why we love the Ford Raptor, and why the RAM Rebel TRX garnered so much attention when it launched last week. It's also why GMC has given the Sierra HD a rough, tough makeover. The Sierra HD All Terrain X is readier than ever to take on the wilderness, and look good while it's doing it.

Under the skin, the All Terrain X has been fitted out with the toughest off-road hardware GMC could lay its hands on. The standard suspension has been swapped out for the (otherwise optional) Z71 off-road package, an underbody shield and beefier skid plates at the front and rear. A locking rear-differential is also standard, for better traction off the beaten track.

What's the point of having all this extra hardware if the world doesn't know about it? To make sure everyone is aware of what's under the skin, GMC has gone all out with the black marker. Along with the paint job, the wheels and trim have been finished in black, and there are unique bumpers and bed-mounted sports bars fitted as well.

It looks good, even though it stops short of going quite as far as the Ford Raptor or Rebel TRX in the aggression stakes.

Inside, the designers seem to have taken an early lunch, because almost nothing has been changed compared to standard cars. A reversing camera, leather seats and wireless phone charging are all standard, as is the eight-inch central touchscreen. Beyond that, it's the same logically laid out cabin you'd find in a regular Sierra 2500HD.

The All Terrain X package can be coupled with either a petrol or diesel engine. On the petrol side of the ledger there's a 6.0-liter V8 on offer, putting out a relatively mild 360 hp (269 kW) of power and 515 Nm (380 lb.ft) of torque.

Ignore the petrol engine for a moment, because the optional 6.6-liter diesel is where the real fun starts. Along with its impressive 445 hp (332 kW) of power, there's a massive 1,234 Nm (910 lb ft) of torque on tap from the redesigned motor, which is also significantly smoother and quieter than the unit it replaces.

"Nearly everything about the Duramax is new, designed to produce more torque at lower rpm and more confidence when trailering or hauling," says Gary Arvan, chief engineer. "You'll also notice the refinement improvements the moment you start the engine, and appreciate them as you cruise quietly down the highway — with or without a trailer."

Pricing is yet to be announced, but expect to pay a decent premium over the standard Sierra 2500 HD, which starts at US$33,890.

Source: GMC

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