How many miles per gallon does a 3500 diesel get?

In most configurations, a Ram 3500 with the 6.7-liter Cummins diesel averages about 18 miles per gallon combined, with roughly 15–16 mpg in city driving and 21–23 mpg on the highway, depending on drivetrain, cab/bed configuration, and payload.

The Ram 3500 is a heavy-duty pickup built for towing and hauling rather than maximum efficiency. Because fuel economy varies with year, configuration, and how the truck is used, this article breaks down typical ranges, what influences them, and how real-world results compare to official estimates.

What affects the fuel economy of a Ram 3500 diesel?

Several practical factors determine how efficiently a Ram 3500 diesel runs in everyday use. The following list highlights the main variables that can swing fuel economy up or down.

• Drivetrain: Two-wheel drive (2WD) versus four-wheel drive (4WD) changes efficiency, with 4WD typically reducing mpg in mixed driving by a few miles per gallon.


• Body style and weight: Regular, Crew, and Mega Cab configurations with different bed lengths add weight and alter aerodynamics, influencing highway and overall mpg.


• Towing and payload: Heavier loads and towing demands raise engine workload and can significantly lower mpg, especially on hills or in headwinds.


• Transmission and gearing: The diesel Ram 3500 uses a heavy-duty automatic with gear ratios tuned for torque; gearing and shifting behavior affect cruising efficiency.


• Tire choice and aerodynamics: Larger or aggressive tires increase rolling resistance, while proper inflation improves efficiency.


• Driving behavior: Speed, acceleration, and idle time directly affect mpg; smoother driving and steady speeds improve numbers.

In short, the “typical” number is a snapshot; your results depend on how you use the truck day to day.

EPA estimates and real-world numbers

The official EPA ratings for the Ram 3500 diesel depend on the exact configuration (2WD vs 4WD, cab and bed, etc.). In general, these trucks sit in the high teens for combined mpg, with highway numbers often in the low to mid-20s when not towing and under light loads. Real-world numbers can dip in city driving or when the truck is fully loaded or towing, but highway cruising under light load typically approaches the higher end of the range.

To give a sense of typical ranges, here are common configurations and their approximate combined mpg in real-world conditions:

• 2WD Regular Cab / Long Bed: around 18–19 mpg combined, with city around 15 and highway near 23 mpg under light loads.


• 4x4 Crew Cab / Short Bed: around 18–19 mpg combined, with city around 15 and highway around 21–22 mpg when not towing.


• 4x4 Mega Cab / Long Bed: around 17–18 mpg combined, with city in the mid-teens and highway around 21 mpg under moderate loads.

These figures are approximate and can vary by model year, emissions equipment, tire choice, and driving conditions. For exact numbers, check the EPA fuel economy label on the specific configuration you’re considering.

Practical tips to maximize mpg

Small changes can add up in a heavy-duty pickup. Consider these practices to improve efficiency without sacrificing capability:

• Keep up with maintenance: clean air filters, proper oil changes, and component health (turbocharger, exhaust systems) matter for efficiency.


• Maintain correct tire pressure and use fuel-efficient tires where possible to reduce rolling resistance.


• Drive at steady speeds and use cruise control on highways to minimize throttle fluctuations.


• Avoid idling when parked for extended periods and plan routes to minimize stop-and-go driving.


• Tow and payload planning: distribute loads thoughtfully and avoid unnecessary weight when possible.

Improving efficiency is especially valuable for owners who use the Ram 3500 for daily driving alongside occasional heavy work.

Summary

The Ram 3500 diesel typically delivers roughly 18 mpg combined in many common setups, with city driving often in the mid-teens and highway cruising in the low-to-mid-20s when not towing. Real-world results vary based on drivetrain, body configuration, payload, and driving habits. For precise figures, consult the EPA ratings for your exact configuration and consider your typical workload when evaluating fuel costs.

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. 

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 is the fuel mileage on a 6.7 PowerStroke vs 6.7 Cummins?

The Ford 6.7L Powerstroke generally gets better highway mileage, typically between 19–20 MPG when unloaded, while the 6.7L Cummins averages around 16–18 MPG. However, the Cummins often performs better under heavy towing loads due to its high low-end torque. Real-world fuel economy can vary significantly depending on factors like model year, vehicle condition, payload, and driving habits. 
This video compares the performance of a 6.7L Powerstroke and a 6.7L Cummins in a pulling competition: 57sMann Family FarmsYouTube · Jul 3, 2021
6.7L Cummins

• Highway MPG (unloaded): 16–18 MPG
• City MPG: Around 12 MPG
• Towing: Stronger under heavy towing loads due to high low-end torque. 

This video shows a MPG challenge comparing a 6.7L Duramax, 6.7L Cummins, and a 6.7L Powerstroke: 56sThe Fast Lane TruckYouTube · Jun 19, 2018
6.7L Powerstroke

• Highway MPG (unloaded): Up to 20 MPG
• City MPG: Around 14–15 MPG
• Towing: Often slightly less fuel-efficient when towing heavy loads compared to the Cummins. 

Key considerations

• Load: The 6.7L Powerstroke tends to have an advantage in fuel economy when unloaded, but this gap narrows significantly or reverses when towing heavy loads, where the Cummins' torque becomes a benefit. 
• Model Year: Fuel economy can vary between different model years for both engines due to design updates. 
• Driving Conditions: Urban vs. highway driving, speed, and driving habits will all affect the final MPG. 
• Towing/Payload: When a truck is fully loaded, fuel economy drops for both engines. Some drivers report a full load can bring the MPG down to around 11.2 MPG for either engine, though this is highly variable.