Experience rugged capability and premium refinement with this 2021 GMC Sierra 1500 AT4, a truck engineered to deliver power, style, and innovation both on and off the road. With only 39,000 miles, this Sierra stands out as a well-maintained, low-mileage option for anyone seeking a powerful half-ton pickup with true off-road pedigree.
Under the hood, the commanding 6.2L V8 engine provides exceptional performance, delivering robust horsepower and torque that makes towing, hauling, or conquering rough terrain effortless. The AT4s off-road suspension, skid plates, and AT4 High Clearance Step enhance capability while maintaining everyday practicality. Paired with GMCs trail-ready engineering, this truck is equally confident on highways, job sites, and backcountry trails.
Finished in a striking Onyx Black exterior, this Sierra AT4 is complemented by bold 20-inch aluminum wheels, aggressive styling cues, and signature AT4 badging that distinguish it from the crowd. The design balances strength and sophistication, projecting a modern, upscale presence that GMC trucks are known for.
Inside, the cabin blends durability with refinement. The interior features Jet Black leather with Kalahari accents, creating a premium environment with sporty contrast. Thoughtful ergonomics, intuitive technology, and high-quality materials ensure comfort on every drive. With advanced infotainment, driver-assist features, and spacious seating, the Sierra AT4 provides convenience and confidence whether youre commuting or adventuring off the grid.
If youre looking for a truck that delivers the perfect mix of power, ruggedness, and refinement, this 2021 GMC Sierra 1500 AT4 with the 6.2L V8 is an outstanding choice. With its low mileage, premium features, and trail-ready design, its built to exceed expectations.
Used 2021 GMCSierra 1500 AT4 4WD Crew Cab 147 AT4 8for Sale in Michigan City
- Exterior Color
- Onyx Black
- Interior Color
- Jet Black With Kalahari Accents
- Odometer
- 39,508 miles
- Body/Seating
- 4WD Crew Cab 147 AT4/5 seats
- Transmission
- Automatic
- Engine
- 8
- VIN
- 3GTP9EEL0MG403790
- Stock Number
- P1230
GMC
Sierra 1500
Highlighted Features
- Leather upholstery
- Automatic temperature control
- Wireless phone connectivity
- Front dual zone A/C
- Auto-dimming rearview mirror
- Split folding rear seat
- Memory seat
- Heated front seats
- Ventilated front seats
- Perimeter/approach lights
- Remote keyless entry
- Heated steering wheel
Included Packages & Accessories
Detailed Specifications
- 1-touch down
- 1-touch up
- Air conditioning
- Auto-dimming rearview mirror
- Automatic temperature control
- Driver door bin
- Driver vanity mirror
- Front beverage holders
- Front dual zone A/C
- Heated steering wheel
- Illuminated entry
- Memory seat
- Overhead console
- Passenger door bin
- Passenger vanity mirror
- Power windows
- Proximity key: doors and push button start
- Rear beverage holders
- Rear door bins
- Remote engine start: keyfob
- Remote keyless entry
- Speed control
- Telescoping steering wheel
- Tilt steering wheel
- Alloy wheels
- Front anti-roll bar
- Front wheel independent suspension
- Power steering
- Speed-sensing steering
- Tires: all-terrain
- Wheel size: 20"
- 1st row LCD monitors: 2
- Primary LCD size: 8.0"
- Radio data system
- Smart device integration: Apple CarPlay/Android Auto
- Steering wheel mounted audio controls
- Wireless phone connectivity: Bluetooth
- Front center armrest
- Front seats: bucket
- Heated front seats
- Heated rear seats
- Leather upholstery
- Max seating capacity: 5
- Power 2-way driver lumbar support
- Power 2-way passenger lumbar support
- Power driver seat
- Power passenger seat
- Rear seat center armrest
- Rear seats: split-bench
- Rear seats Folding position: fold-up cushion
- Seat Upholstery: leather
- Split folding rear seat
- Ventilated front seats
- Cylinder deactivation
- Drive type: four-wheel
- Engine location: front
- Fuel economy city: 15mpg
- Fuel economy combined: 18mpg
- Fuel economy highway: 19mpg
- Fuel tank capacity: 24.0gal.
- Hybrid traction battery type: none
- Manual-shift auto
- Mode select transmission
- Rear locking differential
- Recommended fuel: Premium Unleaded
- Standard fuel economy fuel type: gasoline
- Torque: 460 lb.-ft. @ 4,100RPM
- Transmission: 10 speed automatic
- Variable valve control
- Ground clearance (min): 276mm (10.9")
- Auto-dimming door mirrors
- Bedliner
- Bumpers: body-color
- Heated door mirrors
- Left rear passenger door: conventional
- Power door mirrors
- Rear cargo: tailgate
- Rear step bumper
- Right rear passenger: conventional
- Skid plates
- Trailer hitch receiver
- Trailer sway control
- Engine displacement: 6.2 L
- Engine torque: 460 lb.-ft. @ 4,100RPM
- Exterior body width: 2,063mm (81.2")
- Exterior height: 1,990mm (78.3")
- Exterior length: 5,885mm (231.7")
- Front headroom: 1,093mm (43.0")
- Front hiproom: 1,554mm (61.2")
- Front legroom: 1,131mm (44.5")
- Front shoulder room: 1,677mm (66.0")
- Rear headroom: 1,019mm (40.1")
- Rear hiproom: 1,530mm (60.2")
- Rear legroom: 1,102mm (43.4")
- Rear shoulder room: 1,655mm (65.2")
- Towing capacity: 3,901kg (8,600lbs)
- Turning radius: 7.1m (23.5')
- Wheelbase: 3,744mm (147.4")
- Appearance: analog
- Compass
- Delay-off headlights
- Front fog lights
- Front reading lights
- Fully automatic headlights
- Low tire pressure warning
- Oil pressure gauge
- Outside temperature display
- Rear reading lights
- Rear window defroster
- Tachometer
- Trip computer
- Variably intermittent wipers
- Voltmeter
- 4 wheel disc brakes
- ABS brakes
- Brake assist
- Dual front impact airbags
- Dual front side impact airbags
- Electronic stability
- Ignition disable
- Occupant sensing airbag
- Overhead airbag
- Panic alarm
- Perimeter/approach lights
- Security system
- Traction control
Dealer Notes
KBB.com Consumer Reviews

Overall4Out of 5
- 3.0
Nice truck
By froggy | on Sunday, December 06, 2020
I purchased this truck brand new and at 3900 miles I started to have a misfire. The warranty put a refurbished rebuilt engine in it. I was not aware that the warranty doesn't put new parts in just refurbished rebuilt parts. I traded in and lost my favorite blue truck. Not a fan of the whole process. Love the truck just not how the warranty went. I would not own another brand or model the 2020 is the nicest riding and looking. Just got a bad motor from the manufacture.… - 5.0
Great Truck
By Mel | on Sunday, April 25, 2021
I love it, I get compliments every where I go, and it apparently worth more than I paid for it brand new, a year and a half later. can't ask for much more than that.… - 5.0
Well done GM
By Tony | on Thursday, November 26, 2020
This truck has a 10 speed transmission that you can barely feel it shift. Traded in an F150 and test drove a similar equipped Ram. Although the Ram was nice, the styling of the GMC won me over, along with the tailgate! It also pulls my boat way better than the Ford, just smoother all around. The cabin is very quiet and the gas mileage is much better than V8 Ford. The cabin is super quiet and the ride is awesome. Love the adaptive cruise control too. The technology is fine and the screen is plenty big. Remember, you are driving this truck, not going to thr drive in! Most importantly, the controls are simple to use and Bose stereo sounds great! Oh, and I got it cheaper than the similar Ram too!…
Based on 88 consumer ratings for 2019–2025 models. | Privacy
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