Home / Pre-Owned Inventory / Used / 2021 / GMC / Sierra 1500 / SLT / 3GTU9DET6MG385874
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Used 2021 GMC Sierra 1500 SLT

VIN: 3GTU9DET6MG385874
Stock #: MG385874

90,275 mi.

Vehicle Details

MPG:22/26 (City/Hwy)
Trans.:10-Speed Automatic
Drivetrain:Four Wheel Drive
Engine: 3.0L I6
Fuel Type:Diesel
Ext. Color:Onyx Black
Int. Color:Jet Black
Port Lavaca Price
$33,990
Document Fee
+$225
Port Lavaca Sale Price
$34,215

Price valid through: June 9, 2026*

people recently viewed this vehicle**
The 2021 GMC Sierra 1500 SLT in Onyx Black with Jet Black interior delivers premium full-size truck comfort, smooth diesel-style torque, and practical 4WD capability for drivers who want more than just a plain work truck. Powered by a 3.0L I6 engine and paired with a 10-speed automatic transmission, this Sierra SLT offers confident towing and hauling ability, composed highway manners, and the kind of upscale everyday drivability that makes it feel equally at home on the ranch, the road, or the jobsite. With 90,275 miles, this Crew Cab still brings strong value, broad buyer appeal, and premium truck utility in a package that knows how to work without feeling stripped down.

Entertainment and Connectivity Features
• Large touchscreen infotainment display
• Apple CarPlay integration
• Android Auto integration
• Bluetooth® hands-free connectivity
• USB charging and media ports
• Steering wheel mounted audio and phone controls
• Voice recognition capability
• Wi-Fi hotspot capability
• Navigation capability
• Digital driver information display

Added Features
• SLT trim package
• Onyx Black exterior
• Jet Black interior
• Four-wheel drive capability
• 3.0L I6 performance
• Crew Cab configuration
• Premium interior appointments
• Strong towing and hauling appeal
• Broad personal-use and work-truck versatility
• Clean upscale GMC styling

Safety Features
• Automatic Emergency Braking
• Forward Collision Alert
• Lane Keep Assist with Lane Departure Warning
• Following Distance Indicator
• HD rear vision camera
• Electronic Stability Control
• Anti-lock braking system
• Tire pressure monitoring system
• Advanced airbag system
• Teen Driver capability

Standard Features
• LED headlamps and LED daytime running lights
• Premium alloy wheels
• Dual-zone automatic climate control
• Power windows and door locks
• Push-button start capability
• Spacious Crew Cab interior
• Fold-up rear seating for added interior flexibility
• Tilt and telescoping steering wheel
• Rear seat air vents
• SLT-specific upscale styling accents

Mechanical Features
• 3.0L I6 engine
• 10-speed automatic transmission
• Four-wheel drive
• Heavy-duty suspension capability
• Four-wheel disc brakes
• Electric power steering
• Strong towing and hauling performance
• Smooth power delivery for daily driving and heavy use
• Built for work, travel, and everyday truck use
• Proven full-size truck practicality

Why drivers choose Port Lavaca Auto Group for their next vehicle

• Trusted dealership serving Texas drivers with transparent, pressure-free buying experiences
• Large selection of quality SUVs, trucks, and cars ready for immediate delivery
• Knowledgeable product specialists who help match drivers with the right vehicle
• Flexible financing options for a wide range of buyers
• Ongoing customer support and service after the sale
• Strong reputation backed by consistent five-star Google reviews

Customer Review Highlight

We shopped around quite a bit before buying, and Port Lavaca Auto Group stood out right away. They were professional, easy to talk to, and made sure everything was clear from start to finish.
Heather W., March 2026

From its practical 4WD capability and premium SLT trim to its roomy Crew Cab comfort and strong everyday truck utility, the 2021 GMC Sierra 1500 is built for drivers who want full-size truck strength, upscale comfort, and value in a pickup that still knows how to earn its keep.

Standard Features

  • Preferred Equipment Group 4SA
  • SLT Convenience Package
  • Texas Edition SLT Premium Package
  • Trailering Package
  • X31 Off-Road & Protection Package
  • X31 Off-Road Package
  • 6 Speakers
  • 6-Speaker Audio System Feature
  • AM/FM radio: SiriusXM with 360L
  • Premium audio system: GMC Infotainment System
  • Radio data system
  • Radio: Premium GMC Infotainment Sys w/Multi-Touch
  • SiriusXM w/360L
  • Steering Wheel Audio Controls
  • Air Conditioning
  • Automatic temperature control
  • Electric Rear-Window Defogger
  • Front dual zone A/C
  • Rear window defroster
  • 12-Volt Rear Auxiliary Power Outlet
  • 120-Volt Bed Mounted Power Outlet
  • 120-Volt Instrument Panel Power Outlet
  • Driver Memory
  • Memory seat
  • Power driver seat
  • Power Front Passenger Windows w/Express Up/Down
  • Power Front Windows w/Driver Express Up/Down
  • Power Rear Windows w/Express Down
  • Power steering
  • Power windows
  • Remote keyless entry
  • Remote Vehicle Starter System
  • Steering wheel mounted audio controls
  • Universal Home Remote
  • Auto-Locking Rear Differential
  • Electrical Lock Control Steering Column
  • Heavy Duty Suspension
  • Manual Tilt-Wheel & Telescoping Steering Column
  • Off-Road Suspension
  • Speed-sensing steering
  • Traction control
  • 4-Wheel Disc Brakes
  • ABS brakes
  • Dual front impact airbags
  • Dual front side impact airbags
  • Front anti-roll bar
  • Front wheel independent suspension
  • Keyless Open & Start
  • Low tire pressure warning
  • Occupant sensing airbag
  • Overhead airbag
  • Power Door Locks
  • Brake assist
  • Electronic Stability Control
  • Hill Descent Control
  • Delay-off headlights
  • Front fog lights
  • Fully automatic headlights
  • Dual Exhaust w/Premium Tips
  • Panic alarm
  • Security system
  • Theft Deterrent System (Unauthorized Entry)
  • Speed control
  • 170 Amp Alternator
  • 220 Amp Alternator
  • Auxiliary External Transmission Oil Cooler
  • Engine Block Heater
  • Heavy-Duty Air Filter
  • Auto-dimming door mirrors
  • Bumpers: chrome
  • Chrome Grille
  • Chrome Wheel To Wheel Assist Steps
  • Front License Plate Kit
  • Heated door mirrors
  • LED Cargo Area Lighting
  • Power door mirrors
  • ProGrade Trailering System
  • Rear step bumper
  • Rear Wheelhouse Liners
  • Spray-On Pickup Bed Liner w/GMC Logo
  • Texas Edition Badging
  • X31 Hard Badge
  • 2 USB Ports
  • 2 USB Ports (1st Row)
  • 4G LTE Wi-Fi Hotspot Capable
  • All-Weather Floor Liner (LPO)
  • Apple CarPlay/Android Auto
  • Auto-dimming Rear-View mirror
  • Color-Keyed Carpeting Floor Covering
  • Compass
  • Driver door bin
  • Driver vanity mirror
  • Floor-Mounted Center Console
  • Front reading lights
  • GMC Connected Access Capable
  • Heated steering wheel
  • Illuminated entry
  • OnStar & GMC Connected Services Capable
  • Outside temperature display
  • Overhead console
  • Passenger vanity mirror
  • Rear Dual USB Charging-Only Ports
  • Rear reading lights
  • Rear seat center armrest
  • Tachometer
  • Telescoping steering wheel
  • Tilt steering wheel
  • Trip computer
  • Voltmeter
  • 10-Way Power Driver Seat Adjuster w/Lumbar
  • 10-Way Power Passenger Seat Adjuster w/Lumbar
  • Front 40/20/40 Split-Bench Seat
  • Front Bucket Seats
  • Heated 2nd Row Outboard Seats
  • Heated Driver & Front Outboard Passenger Seating
  • Heated front seats
  • Perf Leather-Appointed Front Outboard Seat Trim
  • Power passenger seat
  • Split folding rear seat
  • Ventilated Driver & Front Passenger Seats
  • Front Center Armrest w/Storage
  • Passenger door bin
  • Front Frame-Mounted Black Recovery Hooks
  • Hitch Guidance
  • Hitch Guidance w/Hitch View
  • In-Vehicle Trailering App
  • Integrated Trailer Brake Controller
  • 20″ x 9″ Polished Aluminum Wheels
  • Alloy wheels
  • Wheels: 18″ x 8.5″ 6-Spoke Machined Aluminum
  • Deep-Tinted Glass
  • Power Sliding Rear Window w/Rear Defogger
  • Variably intermittent wipers
  • 3.23 Rear Axle Ratio

Vehicle Location

Port Lavaca Ford
1801 Highway 35 South Port Lavaca,
TX 77979-5110

VEHICLE DATA
Certain specifications, prices and equipment data have been provided under license from Chrome Data Solutions (\’Chrome Data\’). © 2026 Chrome Data Solutions, LP. All Rights Reserved. This information is supplied for personal use only and may not be used for any commercial purpose whatsoever without the express written consent of Chrome Data. Chrome Data makes no guarantee or warranty, either expressed or implied, including without limitation any warranty of merchantability or fitness for particular purpose, with respect to the data presented here. All specifications, prices and equipment are subject to change without notice.

ESTIMATE MPG
EPA mileage ratings are supplied by Chrome Data Solutions, LP for comparison purposes only. Your actual mileage will vary, depending on how you drive and maintain your vehicle, driving conditions, battery pack age/condition (hybrid models only) and other factors.

Based on 2019 EPA mileage ratings. Your MPGe/MPG and driving range will vary depending on driving conditions, how you drive and maintain your vehicle, battery-pack age/condition, and other factors.

PRICING
Vehicle pricing is believed to be accurate. Tax, title and registration are not included in prices shown unless otherwise stated. Manufacturer incentives may vary by region and are subject to change. Vehicle information & features are based upon standard equipment and may vary by vehicle. Monthly payments may be higher or lower based upon incentives, qualifying programs, credit qualifications, residency & fees. No claims, or warranties are made to guarantee the accuracy of vehicle pricing, payments or actual equipment. Call to confirm accuracy of any information.

Manufacturer’s Rebate subject to residency restrictions. Any customer not meeting the residency restrictions will receive a dealer discount in the same amount of the manufacturer’s rebate.

*Price valid through: June 9, 2026

**Number of views in last 30 days

Technical Specifications

  • Vehicle Name: GMC Sierra 1500
  • Body Style: Crew Cab Pickup
  • Body Code: E63
  • Drivetrain: Four Wheel Drive
  • Passenger Capacity: 5, 6
  • Gross Axle Wt Rating – Front: 3800
  • Gross Axle Wt Rating – Rear: 3800, 4150
  • Curb Weight – Front: 2839
  • Curb Weight – Rear: 1976
  • EPA Greenhouse Gas Score:
  • Gross Vehicle Weight Rating Cap: 7100, 7200, 7300
  • Fuel Economy Est-Combined: 24
  • EPA Fuel Economy Est – City: 22
  • EPA Fuel Economy Est – Hwy: 26
  • Gross Combined Wt Rating: 15000
  • Dead Weight Hitch – Max Trailer Wt.: 5000
  • Dead Weight Hitch – Max Tongue Wt.: 500
  • Wt Distributing Hitch – Max Trailer Wt.: 8500
  • Wt Distributing Hitch – Max Tongue Wt.: 850
  • Fifth Wheel Hitch – Max Trailer Wt.: 7000
  • Fifth Wheel Hitch – Max Tongue Wt.: 1750
  • Maximum Trailering Capacity: 11700
  • Engine Order Code: LM2
  • Engine Type: Diesel I6
  • Displacement: 3.0L/183
  • Fuel System: Direct Injection
  • SAE Net Horsepower @ RPM: 277 @ 3750
  • SAE Net Torque @ RPM: 460 @ 1500
  • Trans Order Code: MQB, MQE
  • Trans Type: 10, 8
  • Trans Description Cont.: Automatic
  • Trans Description Cont. Again:
  • First Gear Ratio (:1): 4.56, 4.69
  • Second Gear Ratio (:1): 2.97, 2.98
  • Third Gear Ratio (:1): 2.08, 2.15
  • Fourth Gear Ratio (:1): 1.69, 1.8
  • Fifth Gear Ratio (:1): 1.27, 1.52
  • Sixth Gear Ratio (:1): 1.00, 1.28
  • Reverse Ratio (:1): 3.82, 4.86
  • Clutch Size:
  • Trans Power Take Off:
  • Trans PTO Access:
  • Transfer Case Model: Magna
  • Transfer Case Gear Ratio (:1), High: 1.0
  • Transfer Case Gear Ratio (:1), Low: , 2.69
  • Transfer Case Power Take Off:
  • Cold Cranking Amps @ 0° F (Primary): 850
  • Cold Cranking Amps @ 0° F (2nd):
  • Tons/yr of CO2 Emissions @ 15K mi/year: 8.5
  • Maximum Alternator Capacity (amps): 170, 220
  • Maximum Alternator Watts: – TBD –
  • Total Cooling System Capacity: – TBD –
  • Engine Oil Cooler: Yes
  • Frame Type: Hydroformed
  • Suspension Type – Front: Independent
  • Suspension Type – Rear: Solid Axle
  • Spring Capacity – Front: 3800
  • Spring Capacity – Rear: 3850, 4150
  • Axle Type – Front: – TBD –
  • Axle Type – Rear: – TBD –
  • Axle Capacity – Front: 3800
  • Axle Capacity – Rear: 3800, 4150
  • Axle Ratio (:1) – Front: 3.23, 3.42
  • Axle Ratio (:1) – Rear: 3.23, 3.42
  • Shock Absorber Diameter – Front: 50
  • Shock Absorber Diameter – Rear: 50
  • Stabilizer Bar Diameter – Front: 1.30
  • Stabilizer Bar Diameter – Rear:
  • Front Tire Order Code: QAB, QAE, QDF, R3O, XCE, XCK
  • Rear Tire Order Code: QAB, QAE, QDF, R3O, XCE, XCK
  • Spare Tire Order Code: QAQ, XCQ
  • Front Tire Size: 265/65R18SL, 275/50R22SL, 275/60R20, 275/60R20SL, LT275/65R18C
  • Rear Tire Size: 265/65R18SL, 275/50R22SL, 275/60R20, 275/60R20SL, LT275/65R18C
  • Spare Tire Size: 255/80R17SL, 265/70R17SL
  • Front Tire Capacity: – TBD –
  • Rear Tire Capacity: – TBD –
  • Spare Tire Capacity: – TBD –
  • Revolutions/Mile @ 45 mph – Front: – TBD –
  • Revolutions/Mile @ 45 mph – Rear: – TBD –
  • Revolutions/Mile @ 45 mph – Spare: – TBD –
  • Front Wheel Size: 18 x 8.5, 20 x 9.0, 22 x – TBD -, 22 x 9.0
  • Rear Wheel Size: 18 x 8.5, 20 x 9.0, 22 x – TBD -, 22 x 9.0
  • Spare Wheel Size: 17 x – TBD –
  • Front Wheel Material: Aluminum
  • Rear Wheel Material: Aluminum
  • Spare Wheel Material: Steel
  • Steering Type: Electric Rack & Pinion
  • Steering Ratio (:1), On Center: – TBD –
  • Steering Ratio (:1), At Lock: – TBD –
  • Turning Diameter – Curb to Curb: 46.3, 46.9
  • Turning Diameter – Wall to Wall: – TBD –
  • Brake Type: Pwr
  • Brake ABS System: 4-Wheel
  • Brake ABS System (Second Line):
  • Disc – Front (Yes or ): Yes
  • Disc – Rear (Yes or ): Yes
  • Front Brake Rotor Diam x Thickness: 13.5 x 1.18
  • Rear Brake Rotor Diam x Thickness: 13.6 x 0.79
  • Drum – Rear (Yes or ):
  • Rear Drum Diam x Width:
  • Fuel Tank Capacity, Approx: 24
  • Aux Fuel Tank Capacity, Approx:
  • Fuel Tank Location: – TBD –
  • Aux Fuel Tank Location:
  • Front Head Room: 43.03
  • Front Leg Room: 44.53
  • Front Shoulder Room: 66.02
  • Front Hip Room: 61.18
  • Second Head Room: 40.12
  • Second Leg Room: 43.4
  • Second Shoulder Room: 65.16
  • Second Hip Room: 60.24
  • Wheelbase: 147.43
  • Length, Overall: 231.72
  • Width, Max w/o mirrors: 81.24
  • Height, Overall: 75.51
  • Overhang, Front: – TBD –
  • Overhang, Rear w/o bumper: – TBD –
  • Front Bumper to Back of Cab: – TBD –
  • Cab to Axle: – TBD –
  • Cab to End of Frame: – TBD –
  • Ground to Top of Load Floor: – TBD –
  • Ground to Top of Frame: – TBD –
  • Frame Width, Rear: – TBD –
  • Ground Clearance, Front: 8.09
  • Ground Clearance, Rear: 8.09
  • Cargo Box Length @ Floor: 69.92
  • Cargo Box Width @ Top, Rear: – TBD –
  • Cargo Box Width @ Floor: 71.4
  • Cargo Box Width @ Wheelhousings: 50.63
  • Cargo Box (Area) Height: 22.4
  • Tailgate Width: – TBD –
  • Cargo Volume: 62.9
  • Ext’d Cab Cargo Volume: – TBD –
  • Seventh Gear Ratio (:1): 0.85, 1.00
  • Eighth Gear Ratio (:1): 0.65, 0.85
  • Ninth Gear Ratio (:1): , 0.69
  • Tenth Gear Ratio (:1): , 0.63
  • Country of Origin: Mexico GMC Truck
  • Model Group: Sierra
  • Vehicle Segment: Large Pick-up
  • Vehicle Type: Crew Cab
  • Body Cab Style: Crew Cab
  • Bed Style: regular
  • Engine Displacement Units: 3.0, 5.3, 5.3, 6.2
  • Engine Camshaft: DOHC, OHV, OHV, OHV
  • Engine Block Type: aluminum, aluminum, aluminum, aluminum
  • Engine Cylinder Count: 6, 8, 8, 8
  • Engine Valve Count: 2, 2, 2, 4

Special Ford Courtesy Vehicle

Ford Courtesy Vehicles are low mileage used vehicles that are eligible for New Vehicle Retail Incentive Offers and the balance of the New Vehicle Limited Warranty. These vehicles were formerly used by our customers and cared for by our very own service department.

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