How many miles per gallon does a RAM 3500 diesel get?

The Ram 3500 diesel typically delivers around 18 miles per gallon combined, with city mileage around 15 mpg and highway mileage in the low-to-mid 20s, depending on drivetrain and configuration. Real-world results vary with payload, towing, and driving conditions.

Understanding the Ram 3500 diesel and its fuel economy

The Ram 3500 uses a 6.7-liter Cummins Turbo Diesel inline-six engine, paired with a heavy-duty transmission. Fuel economy ratings are provided by the EPA and depend on factors such as drivetrain (2WD vs. 4WD), cab/bed configuration, and payload. While the official numbers offer a baseline, actual mileage can be noticeably affected by towing, hauling, and terrain.

EPA mileage estimates by configuration

Below are typical EPA fuel economy ranges for recent Ram 3500 diesel configurations. Exact numbers can vary by model year, cab style, bed length, and transmission choice.

• 2-Wheel Drive (2WD) with 6.7L Cummins Turbo Diesel: City about 15 mpg; highway about 22–23 mpg; combined around 18–19 mpg.


• 4-Wheel Drive (4WD) with 6.7L Cummins Turbo Diesel: City about 14–15 mpg; highway about 21–22 mpg; combined around 17–18 mpg.

These ranges reflect standard configurations and may differ with updates to engines, transmissions, aerodynamics, and drivetrain tuning. Real-world results will vary, especially with heavy payloads or trailers.

Real-world factors that affect fuel economy

Actual mileage is shaped by a variety of conditions beyond the official numbers. The following factors commonly impact fuel efficiency for a Ram 3500 diesel.

• P payload and towing: Carrying heavy loads or towing reduces mpg compared with light-duty operation.


• Driving style: Smooth acceleration and steady speeds improve efficiency; aggressive driving lowers it.


• Terrain and elevation: Hills, mountains, and headwinds generally reduce mpg; flat, calm conditions help.


• Tire size and inflation: Underinflated tires or non-standard tires increase rolling resistance and lower mpg.


• A/C and accessories: Prolonged use of air conditioning or other power-hungry accessories can reduce fuel economy.


• Maintenance and condition: Regular maintenance, clean filters, and proper oil change intervals support better efficiency.

In practice, you’re likely to see lower mileage when the truck is used for heavy work, and higher mileage during long highway trips with light loads.

Summary

For most Ram 3500 diesel configurations, expect roughly 18 mpg combined on average, with 15 mpg in city driving and about 21–23 mpg on the highway in 2WD setups. Four-wheel drive typically lowers city mpg a notch and highway mpg slightly, bringing combined results closer to the high teens. Real-world results depend on payload, towing, terrain, and driving habits. Always refer to the specific model year’s EPA ratings and consider owner experiences for a practical expectation.

How many miles per gallon does a Ram 3500 diesel get while towing?

A Ram 3500 with a diesel engine typically gets 9-14 mpg while towing, though this can vary significantly based on the weight being towed, terrain, and speed. Heavier loads, steep grades, and higher speeds will decrease the mpg, while lighter loads and flatter, lower speeds will result in better fuel economy, with some users reporting up to 11-12 mpg when towing around 10,000 lbs at 62 mph. 
This video demonstrates the fuel economy of a Ram 3500 while towing a trailer: 1mJB ReviewsYouTube · Feb 18, 2020
Factors affecting towing MPG

• Weight of the trailer: The heavier the trailer, the lower your MPG will be. 
• Terrain: Driving in hilly or mountainous areas will significantly decrease fuel economy compared to driving on flat roads. 
• Speed: Driving at higher speeds will reduce your MPG. 
• Axle ratio: Different axle ratios can impact fuel economy. 
• Engine and model year: Newer models with high-output engines may have different performance characteristics compared to older ones. 
• Environmental factors: Wind speed and temperature can also play a role. 

Examples of real-world MPG while towing

• Towing 16,000 lbs with a 2019 model yielded approximately 9.5 mpg. 
• Towing a 9,999 lbs fifth wheel at 62 mph resulted in 11-12 mpg. 
• Pulling a 24,000 lb trailer resulted in 8-9 mpg in hilly terrain. 
• A user reported 9.5 mpg while towing a 16,500 lb trailer at 70 mph, versus 16.5 mpg empty at the same speed. 

This video shows the results of a towing challenge with a Ram 3500 diesel: 1mThe Fast Lane TruckYouTube · Mar 3, 2020

What kind of fuel mileage does a 6.6 Duramax diesel get?

The 6.6L Duramax engine's MPG varies, but typically ranges from 15-18 MPG for mixed driving and 17-20 MPG for unloaded highway driving. Actual mileage depends heavily on factors like driving conditions, towing, and the specific model year. Some newer models achieve higher efficiency, with a 2025 Silverado HD hitting 20.4 MPG on a controlled highway loop. 
This video shows a fuel economy test of a 2021 Chevy Silverado HD with the 6.6L Duramax engine towing a trailer: 48struckguyjoeYouTube · Jan 15, 2021
Mileage breakdown by driving type: 
This video demonstrates a fuel economy test of a 2024 Chevy Silverado HD Duramax: 57sDaily MotorYouTube · Jun 27, 2023

• Mixed/City: Around 15 MPG or lower, especially with stop-and-go traffic. 
• Highway (unloaded): Typically 17-20 MPG, but can vary with speed. 
• Towing: Expect significantly lower mileage, often in the 10-14 MPG range depending on the load and terrain. 

Factors that influence MPG:

• Towing and load: Hauling heavy loads reduces fuel efficiency. 
• Driving conditions: Hilly terrain or stop-and-go city traffic lowers MPG. 
• Vehicle age and break-in: Newer trucks may improve after an initial break-in period, with some owners reporting increased mileage after a few thousand miles. 
• Other factors: Speed, road conditions, and factors like the truck's emissions system (e.g., temporary DPF regen cycles) can also have an effect. 

You can watch this video to see real-world mileage results for a 2022 GMC Sierra 2500 Duramax: 1mDaily MotorYouTube · Mar 26, 2022

How many miles per gallon does a Ram 3500 6.7 diesel get?

The Ram 3500 with a 6.7L Cummins engine typically gets 16–21 mpg combined, with highway mileage being better than city mileage. Expect around 17 mpg in the city and 22 mpg on the highway for a 4x4 model, though these numbers can range from 15 to 25 mpg depending on factors like driving style, load, and the specific truck configuration. 
Fuel economy by driving type

• City: Around 17 mpg, but can be as low as 13-14 mpg depending on driving conditions. 
• Highway: Typically around 22 mpg, though it can reach 25 mpg under optimal conditions. 
• Towing: Varies significantly, but can range from 10-12 mpg when towing heavy loads. 

Factors that affect MPG

• Towing: Heavier loads will decrease fuel economy. Towing can reduce MPG to 10-12 mpg or lower, depending on the load's weight and your speed. 
• Driving style: Aggressive driving habits will negatively impact fuel efficiency.
• Tire and wheel size: Larger or off-road tires, especially on a leveled truck, can decrease MPG. 
• Engine and transmission: Different engine outputs (standard vs. high output) and transmission options can affect performance and fuel economy. 
• Emissions system: The truck's emissions calibration and DPF regeneration cycles can impact MPG. 

What is the fuel economy of the 2025 Ram 3500 Cummins?

The 2025 Ram 3500 with the 6.7L Cummins turbo diesel is estimated to get around 14-16 MPG in the city and 19-25 MPG on the highway, though this can vary significantly based on factors like towing, driving conditions, and the truck's specific configuration. The EPA does not officially rate these heavy-duty trucks, so real-world mileage will be an estimate.
 
This video shows a real-world MPG test of the 2025 Ram 3500: 57sDoomsday DieselYouTube · Aug 17, 2025
Fuel economy estimates

• City: 14-16 MPG
• Highway: 19-25 MPG
• Combined: Around 14-20 MPG (based on various reviews) 

Factors that affect MPG

• Towing: Towing heavy loads significantly decreases fuel economy. A 2,342-mile test with a 22,500-pound load resulted in about 9 MPG, this MotorTrend review shows. 
• Driving conditions: Real-world mileage depends heavily on how and where you drive, Mountain View Chrysler Dodge Jeep Ram notes. 
• Engine regeneration: A diesel particulate filter (DPF) regeneration process will temporarily lower fuel efficiency. For example, one test showed a drop to 13 MPG during a regeneration, this YouTube video explains. 

You can watch this video to see a comparison of MPG tests for the 2024 and 2025 Ram 3500: 56sJB ReviewsYouTube · May 8, 2025