2024 GMC Sierra 3500HD

The base engine is a 6.6-liter gasoline V8 rated at 401 horsepower and 464 lb-ft of torque. The upgraded engine is a 6.6-liter turbodiesel V8 good for 470 horsepower and 975 lb-ft of torque. Both engines are paired with a 10-speed automatic.

Regular-cab, extended-cab (Double Cab) and crew-cab configurations are offered on the Pro and SLE trims, while the SLT, AT4, Denali and Denali Ultimate trims come only as crew cabs. Dual rear wheels are available on certain configurations to increase towing and payload capacity.

Pro
The base trim is relatively bare-bones and comes with:

• 18-inch steel wheels
• LED headlights and taillights
• Manually adjustable trailering mirrors
• Cargo bed steps
• Rear bumper integrated steps
• Locking tailgate
• 40/20/40-split front bench seat with manual adjustments
• Vinyl bench seat and vinyl floor coverings
• Lockable underseat storage
• Power windows and door locks
• Trailer hitch with seven-pin and four-pin connectors
• 7-inch touchscreen infotainment display
• Wireless Apple CarPlay and Android Auto smartphone integration
• Dual charge/data USB ports
• Six-speaker audio system (crew cab and Double Cab)
• Remote keyless entry
• GM connected services and Wi-Fi hotspot capable
• Cargo bed lighting
• Two-speed transfer case with push-button control

The following safety and driver aids are standard on all Sierra 3500HD trims:

• Lane departure warning (alerts you if the vehicle begins to drift out of its lane)
• Following distance indicator (displays the distance to the car in front and warns if you're following too closely)
• Forward collision alert (warns of a possible collision with the vehicle you are following)
• Automated emergency braking (warns if a front impact is imminent and applies the brakes if you don't respond in time)
• Automatic high beams

SLE
Adds more convenience features such as:

• 18-inch alloy wheels
• 13.4-inch infotainment touchscreen
• Upgraded steering wheel with audio controls
• Navigation
• Power trailering mirrors
• Configurable MultiPro tailgate
• Integrated brake trailer controller (allows adjustment of a trailer's brakes from the cab)
• Cloth seats and carpeted floors
• Cruise control
• 12.3-inch color driver information display
• Satellite radio
• Keyless open

 SLT
The SLT starts moving into premium territory by adding: 

• LED foglights
• Power-folding and -extending heated trailering mirrors
• Electronic variable steering assist (reduces long-distance fatigue)
• 120-volt power outlet in cargo bed and instrument panel
• Remote engine start
• Dual-zone automatic climate control
• Leather seats
• 10-way power-adjustable driver's and front passenger seats
• Driver's seat memory settings
• Heated front seats
• Heated steering wheel
• Second-row USB ports
• High-definition backup camera with hitch-view angle
• Two-speed transfer case with auto mode that automatically engages four-wheel drive
• LED bed lighting

AT4
Comes with most SLT features but adds off-road attitude and capability with:

• Standard four-wheel drive
• 20-inch wheels
• BFGoodrich off-road tires
• Hill descent control
• Off-road suspension tuning with twin-tube dampers
• Underbody skid plates
• Body-color bumpers
• Spray-in bedliner
• Front bucket seats with center console
• Console-mounted USB ports
• Ventilated front seats
• Heated rear outboard seats
• Three years of OnStar Premium service
• Seven-speaker Bose audio system
• Surround-view camera system (gives you a top-down view of the Silverado 3500HD and its surroundings for tight parking situations)
• Bed-view camera
• ProGrade trailering system (trailer light test, customizable trailer profiles, 15 camera views, including transparent trailer)
• Wireless device charging
• Safety alert seat (uses vibrations to alert driver to a potential collision)
• Rear cross-traffic warning (alerts you if a vehicle behind you is about to cross your path while you're in reverse)
• Blind-spot warning (alerts you if a vehicle in the next lane over is in your blind spot)

Denali
GMC's luxury trim with premium features that include:

• 20-inch alloy wheels
• Chrome exterior trim and recovery hooks
• Power-sliding rear window
• Three years of OnStar Premium
• Chrome assist steps
• 12-way power-adjustable seats

Denali Ultimate
Tops the Sierra 3500HD lineup with luxury amenities including:

• 6.6-liter turbodiesel engine
• Unique 20-inch wheels
• Power-retractable assist steps
• Adaptive cruise control
• 16-way power-adjustable and massaging front seats
• 12-speaker Bose audio system
• Premium leather upholstery on seats and door panels
• Head-up display
• Digital rearview mirror
• Sunroof
• Trailer tire-pressure monitoring

There are more than 30 option packages and around two dozen stand-alone options available for the various trims. They generally add features to the lower trims that are standard on the higher trims.