2025 GMC Sierra 2500 Gas Vs. Diesel: Key Differences & Best Choice
If you're shopping for a GMC Sierra 2500 and wondering, "Is a diesel 2500 better than a gas 2500?" then let our GMC 2500 gas vs. diesel MPG, horsepower, torque, towing, and reliability guide get you behind the wheel of your optimal workhorse. While both 6.6-liter V-8 engines offer incredible heft that makes towing nearly anything – from canoes to construction vehicles – a piece of cake, each option provides a different ride for different truck-minded folks. The Jones Buick GMC Casa Grande team is happy to show off the highlights of each vehicle.
GMC 2500: Diesel vs. Gas at a Glance
- The gas engine has lower horsepower and torque than the diesel option.
- The diesel variant can tow up to 22,500 pounds with a gooseneck hitch, while the gas V-8 can haul a still impressive 18,700 pounds.1
- On the flip side, the gas V-8 tends to have better payload ratings across the board than the diesel powertrain.
- In addition, based on average fuel prices, you can expect a lower cost for maintaining and refilling a gas engine.
- However, according to drivers like you, the 6.6-liter Duramax turbo-diesel engine lasts longer and retains resale value for longer than its gas sibling.
GMC Sierra 2500 Gas vs. Diesel Performance
Stepping into the cabin of any 2500 GMC Sierra 2500 is unlocking a world of engine-revving bliss, but the GMC 6.6 gas specs stand apart from its diesel brethren. While the 6.6-liter V-8 gas engine outputs 401 horsepower and 464 pound-feet of torque, the diesel option brings huge muscle with 470 horsepower and 975 pound-feet of torque, upgrading your worksite with adrenaline-pumping potency.
But the 6.6 gas engine specs are just as impressive in their own way. A drive with the standard 2025 Sierra 2500 powertrain provides nearly as much of a thrill as its available diesel drive. You can see that for yourself when you explore new GMC Sierra 2500 vehicles in our showroom!
2025 GMC Sierra 2500: Gas vs. Diesel Engine Comparison
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| Powertrain | 6.6L V-8 gas engine | 6.6L Duramax turbo-diesel V-8 engine |
|---|---|---|
| Horsepower | 401 | 470 |
| Torque | 464 lb-ft | 975 lb-ft |
| Towing Capacity (Conventional) | 16,000 lbs1 | 20,000 lbs1 |
| Towing Capacity (5th-Wheel / Goosneeck) | 18,700 lbs1 | 22,500 lbs1 |
| Max Payload Capacity (2WD) | 3,907 lbs2 | 3,687 lbs2 |
| Max Payload Capacity (4WD) | 3,810 lbs2 | 3,850 lbs2 |
| Fuel Tank Size | 36 gal | 28 - 36 gal |
| Cost Approximation | Lower | Higher |
| Pros |
|
|
| Cons | A less smooth start | Slightly more expensive to maintain and refuel |
GMC Sierra 2500 Towing Capacity Compared
If your decision depends on how the GMC 2500 gas vs. diesel towing comparison pans out, you're probably going to want the Duramax engine. The GMC diesel 2500 powertrain offers up to 20,000 pounds of conventional towing capacity and 22,500 pounds of gooseneck or fifth-wheel towing.1 This immense figure for a three-quarter-ton truck makes you ready and able to handle large boats, flatbeds, livestock carriers, and similar intense towing targets with room to spare.
The gas V-8 creates a 16,000-pound conventional and 18,700-pound fifth-wheel GMC 2500 towing capacity,1 which can still handle massive tasks, if not to the same degree as the diesel engine.
Balancing things a bit is the hauling potential of the gas V-8. While numbers differ vastly depending on your trim level, the standard powertrain has a higher payload capacity compared to the GMC Duramax 2500 version. With a maximum payload of 3,907 pounds,2 your bed will be capable of hauling plenty.
GMC 6.6 Gas vs. 6.6 Diesel MPG Estimations
While the EPA and government organizations do not track data for three-quarter-ton trucks like the GMC Sierra 2500, diesel tends to last longer but costs more than the standard fuel that can power the default powertrain. This means you'll have to refill your 36-gallon gas engine more often than the 28-36-gallon diesel option, but you'll usually pay less to fuel the standard gas model than with the GMC 2500 diesel. Your GMC 2500 gas mileage will be better with the available engine, but the overall price makes the gas V-8 your choice for day-to-day driving, while the diesel engine is for those who want their three-quarter-ton truck to handle any job they throw at it.
Diesel vs. Gas Truck Longevity
Because the diesel engine is refilled less often than its standard sibling and can provide high power with fewer revolutions per minute, you are less likely to run into mechanical issues due to consistent use when compared to a gas powertrain. That means the diesel engine provides a better resale value and likely fewer maintenance trips than the standard gas V-8 – though the more robust parts might make a gas engine less pricey to maintain. Generally, you can expect the diesel V-8 to last longer but potentially cost more than its standard cousin.
Frequently Asked Questions
Which engine has a higher towing capacity?
In general, if your goal is to tow larger trailers, the 6.6-liter Turbo-Diesel Duramax V-8 is an unstoppable force in your GMC 2500. With a conventional towing limit of 20,000 pounds and a gooseneck capability of over 22,000 pounds,1 your full-size truck can tow construction materials, livestock carriers, vehicles, and much more. The gas option is similar but a bit less powerful.
Which engine is better for daily driving?
The 6.6-liter gas V-8 is your premier option for day-to-day driving in your GMC 2500. While the EPA does not rate heavy-duty trucks for fuel efficiency, the gas engine costs less to refill while offering a still-impressive horsepower and tow rating. This makes it slightly better than the diesel powertrain for getting from A to B.
Which engine is better for resale value?
According to market trends, the 6.6-liter Turbo-Diesel Duramax V-8 will often provide a better resale rate when you bring it back to the market. The differences are minor, but the combination of the sturdier diesel powertrain and base market value maintains your truck's longevity and boosts the value of your GMC 2500 over time. For more information, ask our representatives about how to preserve resale value!
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1GM-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.
2These 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.