GMC Sierra 2500HD 2021 Review

One year after a complete redesign that brought more right angles than an architectural firm and more chrome than Chicago's bean-shaped Cloud Gate, the Sierra 2500HD heads into 2021 with a handful of additional improvements. These are mostly related to technology. For instance, the Sierra's available trailer camera system is more capable than last year's setup and can provide more camera views to help make towing even easier. There's also new wireless connectivity for Android Auto and Apple CarPlay smartphone integration, so you no longer have to use a USB cord to connect your phone to use these systems.

On the whole, the Sierra 2500HD is a capable truck. The cab is roomy and comfortable, the bed is deep and useful (especially with the available MultiPro tailgate), and GMC provides helpful built-in steps to access the cargo area. But the Sierra's towing and hauling capabilities are a little lower than those of the rival Ford F-250 and Ram 2500, and its cabin is nothing special either. Read our Expert Rating below to get our full review of the Sierra 2500HD's high points and low points.

The Sierra 2500HD is a heavy-duty full-size pickup truck. It's available as a regular cab, double cab (a four-door crew cab but with a smaller rear seating area) and full crew cab. If you're buying a Sierra 2500HD for work, you're likely to want the Sierra or SLE versions of this truck. The SLT serves as the broadest structural beam over the Sierra 2500HD's collection of trim levels. If you want a specialized off-road-tuned or luxury model, the AT4 and Denali stand ready to serve, each equipped with standard four-wheel drive.

Each comes standard with a 6.6-liter gasoline V8 engine (401 horsepower, 464 lb-ft of torque) hooked to a six-speed automatic transmission. A 6.6-liter diesel V8 engine (445 hp, 910 lb-ft) dubbed the Duramax is optional and uses a 10-speed automatic.

Sierra This base trim starts you off with:

• 17-inch steel wheels
• Manually adjustable trailering mirrors
• Cargo bed step points
• Locking tailgate and spare tire carrier
• 40/20/40-split front bench seat
• Vinyl seats and floor coverings
• Manual windows and door locks
• Trailering hitch
• 7-inch touchscreen infotainment display
• Simultaneous Bluetooth pairing for two devices
• Apple CarPlay and Android Auto smartphone integration

SLE Adds more convenience features, such as:

• 17-inch alloy wheels
• Upgraded exterior trim
• Power trailering mirrors
• MultiPro tailgate (six configurations)
• Integrated brake trailer controller (allows adjustment of a trailer's brakes from the cab)
• Cloth seats and carpeted floors
• Front underseat storage
• Cruise control
• Power door locks and windows
• Remote keyless entry
• 4.2-inch color driver information display
• Satellite radio
• Connected services including a Wi-Fi hotspot

SLT More luxurious than the SLE, the SLT has:

• 18-inch alloy wheels
• All-terrain tires
• LED headlights
• Power-folding and -extending trailering mirrors
• Cargo bed lighting
• 120-volt power outlet in cargo bed
• Keyless access with push-button engine start
• Remote engine start
• Dual-zone automatic climate control
• Leather seats
• Power-adjustable driver's seat
• Heated front seats
• Heated steering wheel
• 8-inch touchscreen infotainment system display
• Wireless Apple CarPlay and Android Auto
• High-definition backup camera with Hitch View angle

AT4 Provides more off-road attitude and capability with:

• Standard four-wheel drive
• Hill descent control
• Off-road suspension tuning
• Underbody skid plates
• Body-colored bumpers
• Spray-in bedliner
• Front bucket seats with center console
• Ventilated front seats
• Heated rear outboard seats

Denali Tops the Sierra 2500HD lineup and adds on:

• 20-inch alloy wheels
• Automatic high-beam headlights
• Chrome exterior trim
• Power-sliding rear window
• Side steps to ease cab entry and exit
• Premium leather seats
• Upgraded driver information display
• Navigation system
• Bose premium sound system
• Wireless smartphone charging
• Bed-view camera

The Denali trim also includes the following safety systems, many of which are available as options on other versions of the Sierra 2500HD:

• Forward collision mitigation (warns you of an impending collision and applies the brakes in certain scenarios)
• Lane departure warning (alerts you if the vehicle begins to drift out of its lane)
• Blind-spot monitoring with rear cross-traffic alert (warns you if a vehicle is in your blind spot during a lane change or while reversing)
• Surround-view camera system (gives you a top-down view of the Sierra 2500HD and its surroundings for tight parking situations)
• Parking sensors (alert you to obstacles that may not be visible in front of or behind the vehicle when parking)

Many of the standard features on the upper trim levels are available on the lower trims as options. Other major options, depending on on the trim level, include:

• Head-up display (displays important information in your sight line onto the windshield)
• Trailering camera system (can display multiple trailer-based camera views on the touchscreen to aid with towing)
• Digital rearview mirror (allows you to see out the back even with a fully loaded cargo area)
• X31 off-road package (upgraded suspension, skid plates, hill decent control)