If you're looking at the 2024 Ram 2500 6.4 Hemi mpg ratings, you already know you aren't shopping for a Prius. You're looking at a heavy-duty beast designed to haul trailers, carry heavy payloads, and generally do the kind of work that smaller trucks just can't handle. But even when you're buying a 3/4-ton truck, the cost of fuel is a massive part of the ownership equation. Nobody likes spending more time at the gas station than they have to, especially with a 31 or 50-gallon tank to fill.
The 6.4-liter Hemi V8, often called the "392" by enthusiasts, is a legendary powerhouse. It's the standard engine for the Ram 2500, and for many owners, it's the preferred choice over the Cummins diesel because of the lower upfront cost and simpler maintenance. But how does it actually perform when it comes to fuel economy? Let's break down what you can really expect when you get behind the wheel.
The Reality of Heavy-Duty Fuel Economy
The first thing you'll notice when searching for official numbers is that the EPA doesn't actually rate heavy-duty trucks like the Ram 2500. Because these vehicles have a Gross Vehicle Weight Rating (GVWR) over 8,500 pounds, manufacturers aren't required to put those familiar city/highway stickers on the window. This leaves a lot of potential buyers guessing.
Based on real-world testing and feedback from long-term owners, the 2024 Ram 2500 6.4 Hemi mpg usually lands somewhere between 11 and 15 miles per gallon for combined driving. If you're strictly cruising on the highway at a reasonable speed—think 65 to 70 mph—you might see it climb up to 16 or even 17 mpg on a good day with a tailwind. However, once you start navigating stop-and-go city traffic, don't be surprised if that number dips into the high single digits or stays around 10 mpg.
What Influences the Numbers?
Not every 2024 Ram 2500 is built the same, and small changes in the configuration can lead to different results at the pump. It's not just about the engine; it's about how the truck is geared and what it's carrying.
Rear Axle Ratios
One of the biggest factors in your fuel economy is the rear axle ratio. Most Ram 2500s come with either a 3.73 or a 4.10 gear ratio. If you have the 3.73 gears, your engine will turn at lower RPMs while cruising on the highway, which generally helps your fuel economy. On the other hand, the 4.10 ratio is better for getting heavy loads moving, but it'll cost you about 1-2 mpg on the highway because the engine has to work a bit harder at speed.
The 8-Speed Transmission
Thankfully, the modern 8-speed ZF-sourced automatic transmission does a lot of heavy lifting to keep the 2024 Ram 2500 6.4 Hemi mpg as respectable as possible. With more gears to choose from, the truck can stay in its "sweet spot" more often. The older 6-speed units used to struggle more, but this 8-speed is smooth and helps the V8 breathe a bit easier, especially when you aren't towing.
Multi-Displacement System (MDS)
The 6.4 Hemi features cylinder deactivation technology, which Ram calls MDS. When you're cruising on a flat road with very little load, the engine can shut down four of its eight cylinders to save gas. You'll often see an "ECO" light pop up on the dash when this happens. While it won't turn your truck into a fuel-sipper, it definitely helps squeeze an extra mile or two out of a highway trip.
Towing and Hauling Impact
Let's be honest: you didn't buy a Ram 2500 to drive it empty all the time. When you hook up a trailer, the 2024 Ram 2500 6.4 Hemi mpg takes a predictable hit.
If you're pulling a 10,000-pound travel trailer or a large boat, your fuel economy is likely going to drop into the 7 to 9 mpg range. Heavy-duty gas engines have to work significantly harder than diesels to maintain speed while towing, and they consume a lot of fuel to generate that necessary torque. If you tow heavy loads daily across long distances, this is where the Hemi starts to feel expensive compared to the Cummins diesel. But for the weekend warrior or the occasional hauler, the gas engine's lower maintenance costs often balance out the higher fuel bill.
Gas vs. Diesel: The Financial Trade-off
When people talk about the 2024 Ram 2500 6.4 Hemi mpg, they almost always compare it to the 6.7L Cummins Turbo Diesel. There's no denying the diesel gets better mileage—often seeing 18-20 mpg on the highway—but you have to look at the "hidden" costs.
The Cummins is a roughly $9,500 upcharge. On top of that, diesel fuel is usually more expensive than 89-octane gas, and you have to deal with DEF (Diesel Exhaust Fluid) and more expensive oil changes. For a lot of people, you'd have to drive 100,000 miles before the fuel savings of the diesel actually pay for the initial cost of the engine. If you're mostly doing short trips or using the truck as a daily driver with occasional towing, the 6.4 Hemi is often the smarter financial move, even if the mpg numbers look scarier on paper.
Tips for Better Mileage
If you've already got a 2024 Ram 2500 in your driveway and you're looking to improve your numbers, there are a few things you can do. It sounds simple, but your right foot is the biggest variable.
- Watch the Speed: Drag increases significantly once you go over 70 mph. Keeping your cruise control set at 65 mph can make a noticeable difference in your average mpg.
- Check Your Tires: Running heavy mud tires or under-inflated tires will kill your fuel economy. Stick to all-terrain or highway treads and keep them at the recommended PSI.
- Lose the Weight: If you have 300 pounds of tools or debris in the bed that you don't need for the day, take them out. Every bit of weight requires more energy to move.
- Use Recommended Fuel: While the 6.4 Hemi can run on 87 octane, Ram recommends 89 for the best performance and efficiency. Some owners find that the slight bump in price for mid-grade pays for itself with slightly better mileage and a smoother-running engine.
Is the 6.4 Hemi Right for You?
At the end of the day, the 2024 Ram 2500 6.4 Hemi mpg is exactly what you'd expect from a massive, naturally aspirated V8 in a heavy steel frame. It's built for durability and power, not for winning fuel economy awards.
If you can live with 12-14 mpg in exchange for a truck that is simpler to maintain, cheaper to buy, and sounds absolutely fantastic when you step on it, the 6.4 Hemi is a great choice. It's a reliable workhorse that doesn't complain when you put it to work. Just make sure you've got a good rewards card for your favorite gas station, and you'll be just fine.
Owning a heavy-duty truck is about capability, and the Ram 2500 has that in spades. Whether you're hauling a camper to the mountains or just need a rig that can handle a massive payload, the 6.4 Hemi gets the job done—even if it is a bit thirsty while doing it.