Vehicle Details
Body Style
Truck
Engine
3.0L 6Cyl
Exterior Colour
Black
Interior Colour
Black
Transmission
Automatic
Drivetrain
4×4
Stock
18-260368
Fuel Type
Diesel
Trim Details
Crew Cab Short Box 4-Wheel Drive AT4
Description
2026 GMC Sierra AT4 Crew Cab – Duramax Diesel
This is where refinement shakes hands with the wild. The 2026 GMC Sierra AT4 Crew Cab in Onyx Black is built for drivers who want diesel efficiency, off-road grit, and premium comfort… all in one unapologetically bold truck.
3.0L Duramax Turbo-Diesel – Quiet Strength, Serious Torque
Under the hood, this AT4 doesn’t roar… it pulls:
• 3.0L Duramax Turbo-Diesel I6 • 305 horsepower / 495 lb-ft of torque • Smooth, efficient, and built for long hauls
Perfect for towing, road trips, or just enjoying that effortless diesel surge.
10-Speed Automatic – Always in the Sweet Spot
• 10-speed automatic transmission • Tow/haul mode with grade braking • Paddle shifters for control when you want it
It adapts like a seasoned co-pilot, always finding the right gear.
AT4 Off-Road DNA
This Sierra is born to leave the pavement behind:
• All-terrain tires with off-road suspension tuning • Off-Road High Clearance Steps (AT4 Premium Package) • Factory skid protection and rugged stance
From job sites to backcountry trails, it’s ready to wander without hesitation.
Bold AT4 Presence
• 20" machined aluminum wheels with Carbon Grey accents • Onyx Black exterior for a stealthy, commanding look • Signature AT4 design cues throughout
It doesn’t just show up… it makes an entrance.
Premium Interior – Built for the Long Haul
Inside, it’s all about rugged luxury:
• Perforated leather seats with Kalahari accents • Heated comfort and premium finishes throughout • Power sunroof bringing the outside in
It’s the kind of cabin that makes even long drives feel like short ones.
Technology That Works With You
Loaded with smart features:
• 13.4" GMC Infotainment System with Google Built-In • Wireless Apple CarPlay & Android Auto • Multicolour 15" Head-Up Display • Rear Camera Mirror with full display
Everything you need, right where you expect it.
Advanced Visibility & Trailering Tech
• Bed View Camera for cargo and hitch visibility • Rear Camera Mirror for unobstructed rear view • Trailer Camera Provisions
Backing up, hooking up, and hauling out just got easier.
AT4 Premium & Preferred Packages
This truck is stacked with functional upgrades:
• Universal Home Remote • Power rear sliding window • Off-Road High Clearance Steps • Enhanced convenience and usability features
Practical Capability Meets Everyday Use
• Hard folding truck bed cover • Sport steps (black, dealer-installed) • Engine block heater for Canadian winters
Work during the week. Escape on the weekend.
Added Value
• 3 Years of SiriusXM
Why Buy from Boyer Chevrolet Buick GMC Ajax?
At Boyer Chevrolet Buick GMC Ajax, located at 425 Bayly Street West, you’re backed by a team that understands trucks inside and out, with a 4.7-star rating and over 1,500 reviews.
You get:
• Truck experts who understand towing, diesel, and off-road needs • Competitive financing options • A trusted dealership serving Ajax, Whitby, Oshawa & Durham Region • Full support before and after the sale
The Perfect Balance of Muscle & Refinement
If you’re cross-shopping the Chevrolet Silverado ZR2, Ram Rebel, or Ford F-150 Tremor, the 2026 GMC Sierra AT4 Duramax delivers a rare blend of diesel efficiency, off-road capability, and premium comfort.
📞 Call 905-427-2500 📍 Visit Boyer Chevrolet Buick GMC Ajax 📅 Book your test drive today
This one doesn’t just go off-road… it brings luxury with it.
Packages & Options
Standard Equipment
Technical Specifications
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AM/FM Stereo
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Auxiliary Audio Input
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Bluetooth Connection
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MP3 Player
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Navigation System
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Smart Device Integration
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Requires Subscription
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Satellite Radio
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Premium Sound System
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Steering Wheel Audio Controls
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WiFi Hotspot
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Aluminum Wheels
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Tires - Front All-Terrain
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Tires - Rear All-Terrain
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Conventional Spare Tire
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Wheel, 17" x 8" (43.2 cm x 20.3 cm) full-size, steel spare
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Wheelhouse liners, rear (Deleted with (PCP) AT4 CarbonPro Edition.)
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Bumper, front, body-colour lower
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Bumper, rear body-colour with corner steps
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Grille (Black chrome header and grille insert bars with gloss black accents.)
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Daytime Running Lights
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LED Headlights
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Automatic Highbeams
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Fog Lamps
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Lighting, perimeter
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Taillamps, LED LED signature taillight with LED stop, turn & reverse and Fade-on/Fade-off animation
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Heated Mirrors
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Mirror Memory
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Power Folding Mirrors
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Power Mirror(s)
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Mirror caps, high gloss Black
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Intermittent Wipers
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Rain Sensing Wipers
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Variable Speed Intermittent Wipers
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Privacy Glass
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Lamps, cargo area, cab mounted integrated with centre high mount stop lamp, with switch in bank on left side of steering wheel
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LED Cargo Area Lighting located in cargo bed activated with switch on centre switch bank or key fob
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Integrated Tailgate Step
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Tailgate, gate function manual with EZ Lift includes power lock and release, includes hitch area light
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Tailgate and bed rail protection caps, top
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Door handles, body-colour
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Bed Liner
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Bucket Seats
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Leather Seats
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Driver Adjustable Lumbar
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Power Driver Seat
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Passenger Adjustable Lumbar
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Power Passenger Seat
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Heated Front Seat(s)
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Mirror Memory
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Seat Memory
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Cooled Front Seat(s)
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Pass-Through Rear Seat
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Rear Bench Seat
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Heated Rear Seat(s)
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Centre Console, floor-mounted with cup holders, cell phone storage, power cord management, hanging file folder capability
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Floor covering, colour-keyed carpeting
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Floor Mats
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Adjustable Steering Wheel
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Steering wheel, wrapped
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Heated Steering Wheel
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Driver Information Centre, enhanced, 12.3" diagonal reconfigurable multicolour digital display
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GMC Premium information Display-13.4" diagonal Multicolour I touch screen
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In-Vehicle Trailering App, System includes checklist, trailer maintenance reminders, trailer security alerts, trailer mileage, tow/haul reminder, trailer electrical diagnostics and Trailer Tire Pressure Monitor System module
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Compass, located in instrument cluster
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Exterior Temperature Display, located in radio display
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Brake lining wear indicator
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Power Windows
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Power Door Locks
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Keyless Entry
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Keyless Start
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Remote Engine Start
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Adaptive Cruise Control
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Cruise Control
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Security System
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Steering column lock, electrical
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Wireless Charging
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Power outlet, interior power outlet, 120-volt (400 watts shared with (KC9) bed mounted power outlet)
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Power outlet, bed mounted, 120-volt (400 watts shared with (KI4) interior power outlet)
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Auxiliary Audio Input
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MP3 Player
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USB ports, (2) charge-only, rear
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A/C
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Climate Control
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Multi-Zone A/C
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Air vents, rear
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Rear Defrost
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Auto-Dimming Rearview Mirror
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Assist handles front A-pillar mounted for driver and passenger, rear B-pillar mounted
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Diesel Fuel
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Straight 6 Cylinder Engine
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Turbocharged
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10-Speed A/T
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A/T
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Transmission w/Dual Shift Mode
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Rear axle, 3.23 ratio
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Pickup bed
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GVWR, 7200 lbs. (3266 kg) (Requires TK10*43 Crew Cab 4WD model with (LZ0) Duramax 3.0L Turbo-Diesel I6 engine.)
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Keyless Start
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Air filter, heavy-duty
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Automatic Stop/Start
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Hill Descent Control
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Locking/Limited Slip Differential
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Transfer case, two-speed, electronic Autotrac with push button control (4WD models only)
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Suspension, Off-Road with 2" factory installed lift and monotube shocks
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Four Wheel Drive
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Alternator, 220 amps
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Battery, heavy-duty 850 cold-cranking amps/95 Amp-hr, maintenance-free with rundown protection and retained accessory power (Included and only available with (LZ0) Duramax 3.0L Turbo-Diesel I6 engine.)
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Frame, fully-boxed, hydroformed front section
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Trailer brake controller, integrated
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Tow Hooks
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Skid Plates
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Cargo tie downs (12), fixed, rated at 500 lbs per corner
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Power Steering
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4-Wheel Disc Brakes
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ABS
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Exhaust, dual system (Includes chrome exhaust tips. Not available with (L87) 6.2L EcoTec3 V8 engine.)
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Exhaust, aluminized stainless-steel muffler and tailpipe
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Tow Hitch
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Automatic Highbeams
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Front Collision Mitigation
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Front Collision Warning
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Lane Departure Warning
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Lane Keeping Assist
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Front Collision Mitigation
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Front Collision Warning
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Stability Control
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Traction Control
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Daytime Running Lights
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Driver Air Bag
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Front Head Air Bag
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Front Side Air Bag
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Passenger Air Bag
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Passenger Air Bag Sensor
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Rear Head Air Bag
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Requires Subscription
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Telematics
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Hitch View with image adjustment, Pan/Zoom/Tilt
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Hitch Guidance
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Aerial View Display System
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Back-Up Camera
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Trailer Camera Provisions and trailer viewing software
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Rear Parking Aid
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Following Distance Indicator (Included and only available with (PDI) GMC Pro Safety.)
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Lane Departure Warning
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Lane Keeping Assist
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Blind Spot Monitor
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Cross-Traffic Alert
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Rear Pedestrian Alert
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Driver Monitoring
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Seat Belt Adjustable Guide Loops, front row only
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Rear Seat Belt Indicator
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Buckle to Drive prevents vehicle from being shifted out of Park until driver seat belt is fastened; times out after 20 seconds and encourages seat belt use (Included and only available with (PDI) GMC Pro Safety.)
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Tire Pressure Monitor
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Rear Seat Reminder
No matches were found.
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Vehicle NameGMC Sierra 1500
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Body StyleCrew Cab Pickup
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Body CodeE63
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DrivetrainFour Wheel Drive
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Trans Order CodeMQC
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Trans Type10
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Trans Description Cont.Automatic
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First Gear Ratio (:1)4.70
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Second Gear Ratio (:1)2.99
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Third Gear Ratio (:1)2.15
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Fourth Gear Ratio (:1)1.77
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Fifth Gear Ratio (:1)1.52
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Sixth Gear Ratio (:1)1.28
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Seventh Gear Ratio (:1)1.00
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Eighth Gear Ratio (:1)0.85
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Ninth Gear Ratio (:1)0.69
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Tenth Gear Ratio (:1)0.64
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Reverse Ratio (:1)4.87
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Transfer Case ModelMagna MP3023/4
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Transfer Case Gear Ratio (:1), High1.00
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Transfer Case Gear Ratio (:1), Low2.69
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Passenger Capacity5
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Front Head Room (in)43.03
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Front Leg Room (in)44.53
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Front Shoulder Room (in)64.54
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Front Hip Room (in)60.78
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Second Head Room (in)40.12
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Second Leg Room (in)43.4
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Second Shoulder Room (in)64
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Second Hip Room (in)59.24
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Gross Axle Wt Rating - Front (lbs)3800
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Gross Axle Wt Rating - Rear (lbs)3800
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Curb Weight - Front (lbs)2845
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Curb Weight - Rear (lbs)1981
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Gross Vehicle Weight Rating Cap (lbs)7200
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Gross Combined Wt Rating (lbs)15000
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EnerGuide Estimate - City (L/100 km)10.7
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EnerGuide Estimate - Hwy (L/100 km)9.3
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G/km Of CO2 Emissions270
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Dead Weight Hitch - Max Trailer Wt. (lbs)5000
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Dead Weight Hitch - Max Tongue Wt. (lbs)500
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Wt Distributing Hitch - Max Trailer Wt. (lbs)8700
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Wt Distributing Hitch - Max Tongue Wt. (lbs)870
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Fifth Wheel Hitch - Max Trailer Wt. (lbs)6700
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Fifth Wheel Hitch - Max Tongue Wt. (lbs)1675
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Maximum Trailering Capacity (lbs)9000
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Engine TypeTurbocharged Diesel I6
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Fuel SystemDirect Injection
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Engine Order CodeLZ0
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Displacement3.0L/183
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SAE Net Horsepower @ RPM305 @ 3750
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SAE Net Torque @ RPM495 @ 2750
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Cold Cranking Amps @ 0° F (Primary)850
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Maximum Alternator Capacity (amps)220
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Frame TypeHydroformed
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Suspension Type - FrontIndependent
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Suspension Type - RearSolid Axle
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Spring Capacity - Front (lbs)3800
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Spring Capacity - Rear (lbs)3850
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Axle Capacity - Front (lbs)3800
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Axle Capacity - Rear (lbs)3800
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Axle Ratio (:1) - Front3.23
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Axle Ratio (:1) - Rear3.23
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Stabilizer Bar Diameter - Front (in)1.3
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Front Tire Order CodeQAE
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Rear Tire Order CodeQAE
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Spare Tire Order CodeQAQ
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Front Tire Size275/60R20SL
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Rear Tire Size275/60R20SL
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Spare Tire Size255/80R17SL
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Front Tire Capacity (lbs)3800
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Rear Tire Capacity (lbs)3800
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Revolutions/Mile @ 45 mph - Front (Rev/Mile)N/A
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Revolutions/Mile @ 45 mph - Rear (Rev/Mile)N/A
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Revolutions/Mile @ 45 mph - Spare (Rev/Mile)N/A
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Front Wheel Size (in)20 x 9
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Rear Wheel Size (in)20 x 9
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Spare Wheel Size (in)17 x 8
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Front Wheel MaterialAluminum
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Rear Wheel MaterialAluminum
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Spare Wheel MaterialSteel
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Steering TypeElectric Rack & Pinion
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Turning Diameter - Curb to Curb (ft)47.3
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Turning Diameter - Wall to Wall (ft)N/A
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Brake TypePwr
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Brake ABS System4-Wheel
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Disc - FrontYes
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Disc - RearYes
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Front Brake Rotor Diam x Thickness (in)13 x 1.18
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Rear Brake Rotor Diam x Thickness (in)13.6 x 0.79
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Fuel Tank Capacity, Approx (L)91
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Wheelbase (in)148
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Length, Overall (in)232.9
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Width, Max w/o mirrors (in)81.24
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Height, Overall (in)78.35
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Ground Clearance, Front (in)11.1
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Ground Clearance, Rear (in)11.1
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Cargo Box Length @ Floor (in)69.92
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Cargo Box Width @ Floor (in)71.4
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Cargo Box Width @ Wheelhousings (in)50.63
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Cargo Box (Area) Height (in)22.42
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Cargo Volume (ft³)62.9
No matches were found.
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* Plus HST & Licensing. Price includes: Dealer Admin Fee ($599), Etching ($299), Tire Protection ($199), Tire Duty ($22.50), and OMVIC fee ($22.00) Every reasonable effort is made to ensure the accuracy of the information listed above. Vehicle pricing, incentives, options (including standard equipment), and technical specifications listed is for the 2026 GMC Sierra 1500 AT4 may not match the exact vehicle displayed. Please confirm the accuracy of this information with a sales representative.
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