GMC offers the most powerful pickup trucks, with the Sierra 2500 and 3500 outselling their competition left and right. Check out our 2025 GMC Sierra HD lineup guide and find out why these pickups are such a popular work truck.

Performance
Sierra HD pickups come with a standard 6.6L V8 gas engine that yields 401 horsepower at 5200 rpm and 464 lb.-ft. of torque at 4000 rpm. For increased power, there’s an available 6.6L Duramax Turbo-Diesel V8 engine that generates 470 horsepower at 2800 rpm and 975 lb.-ft. of torque at 1600 rpm.
The Sierra 2500 and 3500 both have an Allison 10-speed automatic transmission that’s electronically controlled with overdrive for smooth shifting. This transmission has Tow/Haul mode for better control when towing heavy loads, and auto-grade braking to slow the vehicle on downhill grades.
Towing
The Sierra 2500 and 3500 are excellent choices for drivers with heavy-duty towing needs, especially with the 6.6L Duramax Turbo-Diesel engine. This engine offers a maximum towing capacity of 21,870 pounds on the 2500 and 36,000 pounds on the 3500.
Both models also come with a complete GMC Trailering Package that includes a trailer hitch, a 7-wire electrical harness, 4-pin and 7-pin connectors, a trailering hitch platform, a 2.5-inch receiver hitch, and Hitch Guidance. Hitch Guidance gives you an in-cabin digital view of your trailer and hitch, helping you attach the two with precision.
Exterior
GMC Sierra pickups have several innovative exterior features that improve every workday, such as the CornerStep rear bumper, cargo tie-downs, and cab-mounted cargo lamps. The 2500 has standard 17-inch all-season tires, while the 3500 comes with 18-inch all-terrain tires.
Seating
Sierra HD pickups come with two full bench seats in their cabin, including a 40/20/40 split front bench with an under-seat storage compartment. The rear bench is a 60/40 split with seat bottoms that can be folded up on either side to create more cargo space. There are available front bucket seats for higher Sierra trims, like the AT4 and Denali.
Connectivity
Inside a 2025 Sierra HD pickup, you’ll find a 7-inch GMC Infotainment system with wireless smartphone integration, AM/FM radio, and Bluetooth audio streaming. Using Bluetooth technology, Apple CarPlay and Android Auto sync your phone to the truck for a personalized experience that includes hands-free phone calls and texting your contacts.
Safety
The Sierra HD Pro Safety package offers increased peace of mind when riding in the 2500 or 3500. This package includes Lane Departure Warning, Forward Collision Alert, Front Pedestrian Braking, Buckle to Drive, Automatic Emergency Braking, and more. Other safety features in the Sierra lineup include StabiliTrak electronic stability control, Teen Driver, and Rear Seat Reminder.
Visit Marquardt of Barrington GMC in Barrington, IL, to see the 2025 Sierra lineup!


