How many miles per gallon does a 2015 Ram 3500 diesel get?
In general, a 2015 Ram 3500 equipped with the 6.7-liter Cummins turbo-diesel delivers about 15 miles per gallon in city driving and around 21 mpg on the highway, with a typical combined rating near 17–18 mpg. Real-world results depend on configuration, payload, and driving conditions.
Overview of the 2015 Ram 3500 diesel
The 2015 Ram 3500 is powered by the 6.7-liter Cummins Turbo Diesel inline-6, paired with a heavy-duty transmission (commonly the AISIN 6-speed automatic on most configurations). This setup is designed for high-torque towing and payload rather than sporty efficiency, so fuel economy reflects the truck’s purpose as a heavy hauler rather than a compact car.
EPA fuel economy estimates by configuration
EPA ratings can vary with cab style, bed length, drivetrain (2WD vs. 4WD), and payload. The figures below reflect typical estimates cited for common configurations of the 2015 Ram 3500 diesel. Actual experience may differ based on how the truck is equipped and used.
- 4x2 Regular Cab / Long Bed: approximately 15 mpg city, 21 mpg highway; combined around 17–18 mpg
- 4x4 Crew Cab / Short Bed: approximately 15 mpg city, 20–21 mpg highway; combined around 17 mpg
- 4x4 Crew Cab / Long Bed (heavy payload/towing): generally similar city economy with highway figures slightly lower depending on load
Note: These numbers are EPA estimates from the 2015 model year and are intended to reflect typical configurations. Real-world fuel economy often deviates due to payload, towing, terrain, tire size, and driving style.
Factors that affect fuel economy
Several realities of owning a heavy-duty diesel pickup influence mpg more than in lighter vehicles. Payload, towing weight, hills and headwinds, frequent starts and stops, tire size and pressure, and overall vehicle maintenance all play significant roles in actual fuel economy.
- Payload and towing: Heavier loads reduce mpg, especially on climbs.
- Drivetrain and aerodynamics: 4WD and longer wheelbases can lower efficiency slightly at highway speeds.
- Maintenance and tires: Proper tire inflation, fuel-injector care, and engine upkeep help preserve efficiency.
Even with these factors, diesel engines like the Cummins 6.7L tend to deliver good torque and stable highway efficiency, which is valuable for towing and long-range trips despite lower efficiency compared with lighter pickups.
Tips to maximize mpg on a Ram 3500 diesel
- Keep payload to what you need; excessive load reduces efficiency more than in light-duty trucks.
- Maintain proper tire pressure and use original equipment tires where possible.
- Schedule regular maintenance: air filters, fuel filters, and engine tune-ups help sustain economy.
- Use efficient driving practices: steady speeds on highway, moderate acceleration, and anticipating stops can improve mileage.
- Consider trailer towing best practices: use the appropriate gear and avoid excessive engine RPM during climbs when towing heavy loads.
By following these practices, owners can often optimize fuel economy within the truck’s design limits and use-case scenarios.
Summary
The 2015 Ram 3500 diesel, powered by the 6.7L Cummins engine, typically sits around 15 mpg in city driving and 21 mpg on highways, with a combined figure in the mid to high teens. Configurations with different cab/bed setups and 4WD can shift those numbers slightly, and real-world results depend heavily on payload, towing, and driving conditions. For buyers or owners, understanding these factors helps set expectations and identify ways to optimize efficiency.
Appendix: Quick context on the model
While fuel economy is a useful metric, the 2015 Ram 3500 diesel is engineered for heavy-duty work—towing, hauling, and durability under load—where fuel economy naturally trails lighter-duty pickups. When evaluating mpg, consider your typical use case and how often you’ll be towing or carrying loads.
Summary: The Ram 3500 diesel provides robust torque and capability with EPA estimates generally around 15 mpg city / 21 mpg highway and a mid-teen combined mpg, with real-world numbers influenced by payload, towing, and driving conditions. If mileage is a priority, factor in your typical usage and consider ways to optimize efficiency through maintenance and driving habits.
