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If you want the ultimate work truck, look no further than the 2021 Sierra 2500HD or 3500HD. With a standard 6.6L V8 Turbo-Diesel Injection and a 6-speed transmission or a Duramax 6.6L Turbo-Diesel engine with 10-speed automatic transmission your drive has never been more powerful or smoother. The 2021 Sierra HD makes towing easy with the GMC ProGrade Trailering App, which offers a variety of unique features designed explicitly to improve the trailering experience. The Durabed of the Sierra HD is the most functional bed in its class. Made with high-strength steel, the bed features 12 standard tie-downs, larger CornerStep rear bumper, and offers available features like the GMC MultiPro tailgate.
Sierra 2500HD & 3500HD
Move Mountains.
Engineered to be large and in charge, the monstrous exterior of the Sierra Heavy Duty was built big so you can tow big.
Trailering Mirrors
  • All Sierra Heavy Duty models are equipped with trailering mirrors
  • Sierra HD offers available trailering mirrors that power fold and manually extend and retract, LED rear guidance lamps that help enhanced visibility when backing up with a trailer, lower convex mirror, as well as amber auxiliary clearance lamps
  • Available Power-adjustable trailering mirrors power extend, fold and retract at the touch of a button

Side Bed Step

The standard Side Bed Step conveniently located just in front of the rear wheel arches complements the large CornerStep rear bumper to help provide easy access when grabbing equipment front the cargo bed.

Dual Path Air Induction System

The available Duramax Turbo-Diesel engine includes the Dual Path Air Induction System, which draws dense, cool air through both the hood scoop and the large front grille to provide cooler induction air temperatures to maximize horsepower and help optimize trailering performance. 
Advantage Lighting
  • LED headlamps (high-intensity on SLT, AT4, and Denali)
  • LED taillamps
  • LED daytime running lamps
  • Available LED fog lamps (available on SLE/standard on SLT, AT4, and Denali)
  • Available LED cargo bed lighting (available on SLE/standard on SLT, AT4, and Denali)
  • Wheel molding amber arch lamps over each wheel
  • Available Roof Market Lamps
Available GMC MultiPro Tailgate
The available GMC MultiPro Tailgate offers six distinct functions designed to help improve loading, unloading and accessing the cargo box.
Best-In-Class Heavy Duty Cargo Bed Volume
  • Roll-formed high-strength steel bed floor
  • Best-in-class heavy-duty cargo box volume 
  • Standard: 1970 L (69.6 cu.ft)
  • Long Bed: 2364 L (83.5 cu.ft)
  • 12 cargo tie-down 227 kg (500 lb.) rating per corner
  • Available LED Lighting
  • Available durable spray-on bedliner

CornerStep Rear Bumper

In both corners of the rear bumper, large footwells, lined with an anti-slip texture and sized for large boots, helps make access to the cargo bed easier than ever. Standard on all Heavy-Duty models.
Sierra Heavy Duty's refined and expansive cabin offers advanced, thoughtfully placed technology to help ensure your ride is smooth and smart.
With Intension. 
Enhanced Comfort
  • Available leather-wrapped heated steering wheel
  • Available heated and ventilated leather-appointed front seats
  • Available HVAC system with dual-zone climate control and rear-seat outlets
Ride Confident
  • Sierra HD's elevated driver seat lets you survey the road with absolute confidence and offers comfortable cushions that provide enhanced support during long hauls and while towing
  • Spacious interior best-in-class Crew Cab front head room (1092 mm (43.0")) and leg room (1130 mm (44.5"))
Premium Rear Seat Comfort
Backseat passenger are sure to be comfortable with the available heated rear outboard seats and spacious rear leg room on Crew Cab models.
Ingenious Storage
Smart Rear Seat Storage
Convenient and spacious storage solutions include available rear seatback storage, perfect for stowing a smartphone and your other road trip essentials.
Room For All The Gear You Need
Sierra HD Crew Cab models have ample storage options to pack the stuff you need, with features like rear-folding split bench with under-seat storage. 
Spacious Centre Console
Lighted centre console storage with available lockable console vault accessory, and large lower lockable glove box and upper glove box.
Available Wireless Charging

When on the road in the Sierra Heavy Duty, it's OK to leave the cords at home. The available wireless charging pad, located within easy reach near the cup holders, has excellent charging abilities and keeps your compatible smartphone charged and ready. 

Available Bose Premium Sound System

The available Bose Premium Sound System supplies seven well-placed speakers to produce powerful, high-quality concert-like sound wherever you go.

Engineered to dominate.
The 2021 Sierra Heavy Duty pickup truck offers up to 16,329 kg (36,000 lb) of available max. towing. It's built strong so you can tow strong. Its large drive shaft and rear axle will give you durability and strength. And its brakes and steering offer excellent control. 

Advanced Engines & Transmissions

The 2021 Sierra Heavy Duty truck features advanced engines and transmission that power a confident driving and trailering experience:
  • 6.6L V8 Gas Engine
  • Available 6.6L Duramax Turbo-Diesel V8 Engine with Allison 10-Speed Automatic Transmission

Responsive Suspension

  • AT4 & Denali's independent front suspensions provide excellent wheel alignment, ride control and turnability
  • Live-axle suspension includes two-stage, semielliptic multileaf rear springs to balance payload management and ride quality
Optimum Engine Performance

To help maintain optimal operating temperatures of the available 6.6L Duramax Turbo Diesel V8 engine, a massive 28" variable-speed cooling fan is used. Dense, cool air from the Dual Path Air Induction System is drawn through both the hood scoop and the large grille to maximum horsepower and help optimize trailering performance. The factory-installed Diesel After-Run feature is designed to help cool down the engine following heavy usage.
Stopping & Going Power

Available Digital Variable Steering Assist

Eases driver's steering effort when maneuvering at low speeds, reduces the steering effort needed to return the heavy-duty truck to centre, and adapts to crowned road surfaces, reducing the need to correct steering over long stretches of uneven road. It includes new enhancements to help with driving response, especially when trailering or when carrying a heavy load.

Park Grade Hold Assist

Prevents movement when shifting out of park on a hill and moving a foot from brake to accelerate pedal by automatically applying brakes at each wheel for an extended period of the time while trailering.

Available Auto Electric Parking Brake Assist

To help with positioning, after backing up to a trailer hitch using available Hitch View, Sierra Heavy Duty will automatically apply the parking brake upon shifting into park to avoid unintentional rolling.

Available 2-Speed Automatic Transfer Case

Sierra is the first heavy-duty truck in its class to offer a 2-speed AutoTrac transfer case with an active automatic 4WD setting, which provides seamless shifting between two-and four-wheel drive based on road conditions. 

Available Traction Select System With Tow/Haul Mode and Off-Road Mode

  • Allows you to quickly switch between multiple traction configurations, including Off-Road mode and Tow/Haul mode, to optimize powertrain calibrations, traction control settings and stability control system calibrations for a variety of terrain and driving conditions
  • The system will retain the Tow/Haul setting configurations for up to 4 hours after the vehicle is turned off, eliminating the need to reengage the system when returning a brief stop on a long journey
X31 Off-Road Package
  • Off-road suspension
  • Twin-Tube Rancho shocks
  • Eaton automatic locking rear differential
  • Underbody skid plates
Gooseneck/5th Wheel Hitch Package
  • Hitch platform to accept ball and stamped bed holes with removeable caps installed
  • Bed-mounted 7-pin trailer harness
  • Available Bed View Camera
Technology that delivers a premium driving experience with advanced connectivity and convenience in its Heavy Duty truck.
Innovation at its finest.
Up To 15 Available Camera Views
Easily keep tabs on your truck and trailer with up to 15 different available camera views including HD Surround Vision, Rear Camera Mirror and Bed View Camera.

Available Rear Camera Mirror
The available Rear Camera Mirror uses a camera to provide you a wide and less obstructed view behind the vehicle while you're driving. You can switch between the camera view and a traditional rearview mirror. 

Available First-In-Class 15" Diagonal Head-Up Display
An available multicolour 15" diagonal Head-Up Display (a first in the heavy-duty pickup class), helps you keep your eyes on the road by projecting directly onto the windshield key information.

Available HD Surround Vision
Available HD Surround Vision uses multiple camera to display to a digital overhead image of the area around your vehicle along with Rear Vision Camera or front views. It works at low speeds and may even help you park and avoid nearby objects. You can select additional views on your camera display.
ProGrade Trailering System
The Sierra Heavy Duty pickup is engineered to enhance your trailering experience with the ProGrade Trailering System. This system of intelligent trailering technologies helps streamline the hitching and towing process with integrated tools that helps you tow with commanding control.

Available In-Vehicle Trailering App

To help improve your trailering experience, Sierra Heavy-Duty's available In-Vehicle Trailering App offers custom trailer profiles, trailer statuses including available tire pressure and temperature monitoring, and more. The app is integrated and accessible through Sierra's Infotainment System, with features including:

  • Create 5 custom trailer profiles based on trailer name, trailer type, trailer hitch type
  • The vehicle mobiles app, myGMC mobile app adding convenience when outside the truck or trailer
  • Trailer tire pressure monitoring system that measure pressure and temperature (requires available Trailer Pressure Monitoring Sensors)
  • Trailer Light Sequence, when includes automatic lighting test sequence
  • Maintenance reminders
  • Step-by-Step pre-departure checklists
  • Track trailer mileage and fuel economy

myGMC Mobile App Trailering Features

myGMC mobile app Trailer Features include:

  • Create and manage trailer profiles, even share with other Sierra owners
  • Trailer Light Test: Remotely activate trailer lights to ensure in working order
  • Pre-Departure Checklist: Review a pre-departure checklist, or create your own
  • Trailer Load Calculator: Find out the combined weight of your truck and trailer for a confidence towing experience
  • Trailering Health: View and receive alerts on key compartments of your trailer like tire pressure monitoring and trailer miles
  • Trailering Glossary: Quick reference to trailering related material

Smart Trailer Integration

Sierra Heavy Duty is designed to integrate ASA Electronic iN-command Control System with Global Connect and access through the myGMC mobile app. The system allows owners to monitor and control a range of smart system, such as water tank levels, HVAC controls and even power slide-outs, in compatible recreational trailers equipped with the technology.

Available Jack-Knife Alert

  • Tracks the position of the compatible trailer in relation to the vehicle and if the front of the trailer approaches the rear of the vehicle, an alert is displayed that you're in potential jackknife situation
  • A yellow warning alert will be displayed when truck/trailer angle is 75% into a jackknife scenario
  • A red warning alert will be displayed when truck/trailer angle is 90% into a jackknife scenario
  • Depending on a customer settings for alerts and Safety Alert Seat availability, there will be a chime or haptic alerts associated with warnings

Available Bed View with Zoom Hitch Guidance

  • Provide a close-up view of the receiver hitch for proper alignment when connecting to a compatible trailer with a conventical hitch
  • The parking brake is automatically set when the vehicle is shifted back into park to help hold the alignment in place

Available Rear Trailer View

  • Uses an available customer-installed GM auxiliary accessory camera mounted on the rear of the compatible trailer to show vehicles or objects behind the trailer
  • The view now includes guidelines to assist when backing the trailer into place and a trailer-angle indicator to show the relationship between the truck and trailer

Available Forward and Reverse Rear Side View Bias

  • Provides a line of sight down either side of the truck. When a compatible trailer is connected, you'll see a split view of the left and right sides of the truck and trailer
  • While driving forward or backward with a trailer, the view automatically biases based on the trailer's angle
  • When enabled and driving forward with the turn signal activated, a Trailer Length Indicator displays a red overlay twice the length of the compatible trailer, showing when other vehicles are present and may interfere with your lane-change maneuver
Astounding Audio

MultiPro Audio System by Kicker

When you're camping or tailgating and want to bring your music outdoors - without leaving your Sierra truck running - the available accessory MultiPro Audio System by Kicker is designed to integrate into the MultiPro Tailgate. This 100-watt exterior audio system has full Bluetooth.

Available SiriusXM 360L

SiriusXM with 360L is the newest, most advanced SiriusXM entertainment experience ever offered in a GM vehicle. You get a variety of premium content including 140+ channels of commercial-free music, plus On Demand shows, performance, talk, entertainment, original programming, artist-dedicated channels and much more. 
Seamless Connectivity

Available Amazon Alexa Built-In
Connect to available Amazon Alexa Built-In for instant, hands-free access to music, directions, calls, news, weather and more.
Apple CarPlay
With Apple CarPlay compatibility you have wired or available wireless access to iPhone features such as hands-free phone calls and messaging, Apple Music, Apple Maps and more.
Android Auto
Android Auto gives your compatible smartphone on-the-go access to Android features such as Google Maps, Google Play Music and more via wired or available Wireless Phone Projection.
Available Safety and Driver Assistance Technology
Enhance your awareness of the road and surrounding vehicle with Sierra HD's intelligent safety technologies.

Available Lane Departure Warning

The available Lane Departure Warning can alert you if you might be unintentionally drifting out of detected lane lines so you can quickly take action. It will not alert you if you're using your turn signals or it can quickly take action. It will not alert you if, you're using your turn signals or it detects your may be intentionally steering.

Available Front and Rear Park Assist

Front and Rear Park Assist can provide distance alerts to nearby detected objects in front of or behind your vehicle to help you park and avoid collision at low speeds.

Available Safety Alert Seat

The available Safety Alert Seat uses left, right, or both-side driver seat vibration pulses to help you identify the direction of potential crashes so you can quickly take action. You can also switch to beeping crash avoidance alerts.

Available IntelliBeam - Auto High Beams

When driving conditions are dark, available IntelliBeam - Auto High Beams can automatically turn the vehicle's high-beam headlamps on and off according to surrounding traffic conditions. 

Available Automatic Emergency Braking

The available Automatic Emergency Braking works with Forward Collision Alert to help you avoid or reduce the severity of a front-end collision with a detected vehicle you're following. This feature works at speeds below 80km/h. Camera technology is used to automatically provide hard emergency braking or enhance the driver's hard braking. 

Available Forward Collision Alert

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Available Following Distance Indicator

The available Following Distance Indicator displays the gab time in seconds between your vehicle and a detected vehicle you're following. This can help you decide if you're following much too closely.

Available Rear Cross Traffic Alert

The available Rear Cross Traffic Alert can warn you of detected left or right cross traffic behind your vehicle when you're in Reverse.

Available Lane Change Alert with Side Blind Zone Alert

The available Lane Change Alert with Side Blind Zone Alert can provide side-mirror visual alerts when a detected moving vehicle is quickly approaching or is in your side blind zone. It can help you avoid lane change collisions.