Sierra 2500HD AT4 Crew Cab is exclusive to the GMC brand


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Big jobs require big trucks and the all-new 2020 GMC Sierra 2500 HD rises to the challenge with abundant features and massive tow ratings. So let’s take a ride!

Across every configuration, specific considerations to thicker, lighter, and more advanced materials have been included in the frame, upgraded suspension components, and even in the powertrains themselves, resulting in higher maximum payload and maximum towing numbers.

From an exterior design perspective, the most dramatic changes to the 2020 Sierra HD front ends are in actual size, driven in large part by the added airflow requirements needed for both the diesel and gas engine choices.

The front end still offers dual-intake avenues for cool air, one integrated in the hood, the other through the wider grille, but now also adds a substantial under-bumper mini-grille to direct air to the intercooler for the diesel.

Window beltlines have been lowered for better driver and passenger visibility and the actual bed sill height is lower as well. I especially like that all HDs offer integrated sidesteps on all models for easier, quicker access to anything in the bed.

I got to test drive GMC’s newest off-road package, called the AT4 – which is exclusive to the GMC brand and, with the exception of an anti-roll bar disconnect and winch, this is the closest thing to a Ram 2500 Power Wagon competitor.

The AT4 package for the HD offers bigger wheels and tires, specially tuned Rancho monotube shocks, extra skid-plating underneath, a Traction Select system with a unique Off-Road mode, Hill Descent and hill hold features, a 15-inch color head-up display with an off-road inclinometer, and a high-def surround-view camera.

After taking my AT4 on higher-speed, choppy dirt roads down south in the Redland and then along stretches of the turnpike, I have to say I was quite impressed with how well the suspension handled.

But what about the interior? Well, not a lot to report here. Most all the looks and features are carry-overs from the light-duty trims. I actually thought I might see more drama with better-quality materials and choices. But beyond that, the softer dash materials and stitching choices are still pretty good.

Like all full-size pickups, the Sierra 2500HD has a long list of available trims, features and packages. The standard Sierra kicks things off, followed by the SLE with a few basic upgrades to the cabin and technology. The SLT takes things to another level more befitting a luxury truck of this price. New for this generation is the off-road-focused AT4. And of course at the top of the heap is the Denali.

All trims are available with either a 6.6-liter V8 gasoline engine (401 hp, 464 pound-feet of torque) mated to a six-speed automatic transmission or a 6.6-liter Duramax V8 turbodiesel (445 hp, 910 pound-feet) paired with a 10-speed automatic.

On the fuel economy front, expect 15 mpg city and 20 mpg highway.

But again, for a tougher look and a bit more off-road capability, I recommend the AT4.

MSRP is $57,700 for this model. After adding the Duramax Turbo Diesel for about $9,900 and the AT4 Premium package ($4,200) and the Technology Package ($2,100), my GMC Sierra 2500 HD AT4 topped out at $77,555.

Grant Miller is the publisher of Miami’s Community Newspapers. He may be contacted by calling 305-662-2277 or via email at

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