2025 GMC Sierra Engines And Performance Details
The 2025 GMC Sierra 2500 engine options offer impressive power, torque, and towing capabilities, making this pickup a top contender in the heavy-duty segment. So, what engine comes in the GMC Sierra 2500? Choose between a gas-powered workhorse or a torque-rich diesel powertrain. How much horsepower does the 6.6-liter Duramax Turbo-Diesel V-8 have? The team from Jones Buick GMC Casa Grande is here to guide you through the details of the GMC Sierra 2500 horsepower, incredible torque, tow ratings, and more.
2025 GMC Sierra 2500 Specs at a Glance
- Powerful Performance: Choose between a gas-powered 6.6-liter V-8 or a 6.6-liter Duramax Turbo-Diesel V-8 with 975 pound-feet of torque.
- Standout Towing: When properly equipped, the GMC Sierra 2500 boasts a maximum conventional towing capacity of 20,000 pounds.
- Advanced Transmission: Both engines are paired with the smooth-shifting Allison 10-speed automatic transmission.
- Smart Trailering Tech: Available ProGrade Trailering Technology simplifies hitching, monitoring, maneuvering, and towing.
- Built to Last: A high-strength frame and proven durability make the GMC Sierra 2500 ready for any challenge.
Under the Hood: GMC Sierra 2500 Engine Size & Options
The 2025 GMC Sierra 2500 is built for those who demand serious competence, and it all starts with what's under the hood. With two powerful engine options – a reliable 6.6-liter gas V-8 and a commanding 6.6-liter Duramax Turbo-Diesel V-8 – the Sierra 2500 engine specs offer the muscle to conquer heavy loads and manage intensive worksites with ease.
The GMC Sierra 2500 gas engine kicks things off and isn't shy about it. Paired with an Allison 10-speed automatic transmission, this powertrain delivers a formidable 401 horsepower and 464 pound-feet of torque and is standard on almost every Sierra 2500 trim.
For those looking to up their GMC Sierra 2500 horsepower and achieve massive torque, the 6.6-liter Duramax Turbo-Diesel V-8 engine takes the lead with 470 horsepower and a jaw-dropping 975 pound-feet of torque. This mighty powertrain is available on every trim level but comes standard on the top-tier Denali Ultimate. This engine is also paired with the same Allison 10-speed automatic transmission.
2025 GMC Sierra 2500 Engine Options by Trim
| Trim Level | 6.6L Gas V-8 | 6.6L Duramax Turbo-Diesel V-8 |
| Pro | Standard | Available |
| SLE | Standard | Available |
| SLT | Standard | Available |
| AT4 | Standard | Available |
| Denali | Standard | Available |
| AT4X | Standard | Available |
| Denali Ultimate | Not Available | Standard |
GMC Sierra 2500 Payload Capacity & Tow Rating
Whether you're hauling heavy equipment or towing large trailers, both GMC Sierra 2500 engine options deliver the strength and reliability you need. Payload capacity varies by configuration, but when equipped with the Duramax diesel engine, the Sierra 2500 tops out at 3,859 pounds.1 Opting for the 6.6-liter gas V-8 offers a slight edge in payload, with a maximum rating of up to 3,907 pounds1 – ideal for those who prioritize hauling over towing.
Towing, however, is a different story. The 6.6-liter Duramax Turbo-Diesel V-8 shines in this regard, giving your 2025 GMC Sierra 2500 the ability to tow up to 20,000 pounds when properly equipped, which is the same as the popular 2024 model. If you're towing with a gooseneck trailer, that capacity jumps to 21,870 pounds. 2 The GMC Sierra 2500 weight increases when equipped with the available Duramax diesel engine, which adds extra mass to the truck – enhancing towing stability and control, especially when handling heavy loads.
However, the GMC Sierra 2500 gas engine is no slouch. Visit us to dig deeper into the towing comparison as you configure your model.
No matter if you need a truck for hauling construction materials or a towing titan for those heavy trailers, you can explore all the trims and configurations in our GMC Sierra 2500 inventory online.
2025 vs. 2024 GMC Sierra 2500 Engine Specs
The 2025 GMC Sierra 2500 carries over the engine upgrades introduced in the 2024 model. While there are minor updates in the engine specs, the core figures remain largely consistent between the model years.
| 2025 GMC Sierra 2500 | 2024 GMC Sierra 2500 | |
| Gas Engine | 6.6L V-8 (401 hp / 464 lb-ft) | 6.6L V-8 (401 hp / 464 lb-ft) |
| Diesel Engine | 6.6L Duramax Turbo-Diesel V-8 (470 hp / 975 lb-ft) | 6.6L Duramax Turbo-Diesel V-8 (470 hp / 975 lb-ft) |
| Transmission | Allison 10-speed automatic (gas & diesel) | Allison 10-speed automatic (gas & diesel) |
| Max Conventional Towing Capacity | 20,000 lbs2 (Turbo-Diesel) | 20,000 lbs2 (Turbo-Diesel) |
GMC Sierra 2500 Performance & Safety
Boast your overall capability with a number of performance features:
- Integrated Power Take-Off: Available on the Allison 10-speed automatic transmission with the Duramax diesel engine and select trims, this feature allows the Sierra 2500 to power external equipment, making it perfect for running tools or hydraulic systems on the job.
- ProGrade Trailering Tech: Includes available features like a Multi-View Camera System, Trailer Side Blind Zone Alert, and Integrated Trailer Brake Control.
- Sierra HD Pro Safety: No matter the engine you choose, all GMC Sierra 2500 models come standard with a suite of safety and driver-assistance features, including Automatic Emergency Braking, Forward Collision Alert, and Following Distance Indicator.
Learn More About the 2025 GMC Sierra Engine Options!
Ready to get behind the wheel of this dominant pickup? Schedule your test drive to experience the raw power of either engine option firsthand. Don't forget to ask about our latest Buick GMC lease specials and financing offers to get the best value on your new GMC Sierra 2500 or the light-duty Sierra 1500.
From the rugged GMC Sierra 2500 to the versatile GMC Canyon, new Buick GMC vehicles are engineered for durability, performance, and long-lasting reliability – ready to tackle whatever the road throws your way.
Frequently Asked Questions
Is the diesel engine better for towing compared to the gas engine?
The GMC Sierra 2500 equipped with the Duramax diesel engine is the superior choice for towing, offering a maximum gooseneck trailering capacity of up to 21,870 pounds when properly equipped. The gas engine has a lower capacity, though it's still a heavy-duty performer. Overall, the diesel powertrain is best suited for handling the most demanding heavy-duty towing tasks.
Does the Sierra 2500 come with an exhaust brake feature?
Yes, the 2025 Sierra 2500 comes with a standard exhaust brake feature when equipped with the 6.6-liter Duramax Turbo-Diesel V-8 engine. This feature enhances control when hauling heavy loads, especially on steep descents. The exhaust brake works by restricting the engine's exhaust flow, which helps slow the vehicle and reduces the need to apply the standard brakes.
Are there any performance-enhancing features available for the Sierra 2500?
The 2025 GMC Sierra 2500 heavy-duty truck offers a range of performance-enhancing features designed to elevate capability and control. Key highlights include an available advanced trailering system with multiple camera views, Hill Descent Control, off-road-tuned suspension on the AT4 trim, and the exhaust brake feature for improved downhill braking with heavy loads – standard on diesel engine models.
Connect With Us to Learn More about the 2025 GMC Sierra 2500
1These maximum payload ratings are intended for comparison purposes only. Before you buy a vehicle or use it to haul people or cargo, carefully review the vehicle loading section of the Owner’s Manual and check the carrying capacity of your specific vehicle on the label on the inside of the driver’s door jamb.
2GM-estimated. Maximum trailering ratings are intended for comparison purposes only. Before you buy a vehicle or use it for trailering, carefully review the trailering section of the Owner’s Manual. The trailering capacity of your specific vehicle may vary. The weight of passengers, cargo and options or accessories may reduce the amount you can trailer.