Onyx Black 2025 GMC Sierra 3500HD AT4 AT4 Duramax 6.6L V8 Turbodiesel AT4 Preferred Package (LED Smoked Amber Roof Marker Lamps, Power Sliding Rear Window w/Defogger, and Universal Home Remote), AT4 Premium Plus Package (Off-Road High Clearance Step (LPO) and Power Sunroof), Gooseneck/5th Wheel Prep Package, Preferred Equipment Group 4SB (120-Volt Bed Mounted Power Outlet, 120-Volt Instrument Panel Power Outlet, 2 Charge-Only Rear USB Ports, 2 Charge/Data USB Ports Inside Center Console, 2 USB Ports, 2-Speed Active Transfer Case, Bed View Camera w/2 Trailer Camera Provisions, Bose Premium 7-Speaker Sound System, Deep-Tinted Glass, Electric Rear-Window Defogger, Floor-Mounted Center Console, Front Rain-Sensing Wipers, Gloss Black Header & Grille Insert Bars, HD Surround Vision, Heated 2nd Row Outboard Seats, Heated Driver & Front Outboard Passenger Seats, Keyless Open & Start, LED Cargo Area Lighting, Manual Tilt-Wheel/Telescoping Steering Column, Power Front Windows w/Passenger Express Up/Down, Prem Front Floor Liners w/Removable Carpet Insert, Prem Rear Floor Liners w/Removable Carpet Insert, Push Button Start, Rear Cross Traffic Alert, Rear Wheelhouse Liners, Remote Vehicle Starter System, Safety Alert Seat, SiriusXM w/360L Trial Subscription, Spray-On Pickup Bedliner w/GMC Logo, Steering Wheel Audio Controls, Trailer Camera Provisions, Trailer Side Blind Zone Alert, Ultrasonic Front & Rear Park Assist, Unauthorized Entry Theft-Deterrent System, Ventilated Driver & Front Passenger Seats, Wireless Charging, and Wireless Phone Projection), Technology Package (Auto-Dimming Inside Rearview Mirror w/Camera and Multicolor 15'' Diagonal Head-Up Display), X31 Off-Road Package (Hill Descent Control), 10-Speed Automatic, 4WD, Jet Black With Kalahari Accents Leather, 10-Way Power Driver Seat Adjuster w/Lumbar, 10-Way Power Passenger Seat Adjuster w/Lumbar, 220 Amp Alternator, 3.42 Rear Axle Ratio, 3.73 Rear Axle Ratio, 4-Wheel Disc Brakes, 7 Speakers, ABS brakes, Air Conditi