2015 Ram 2500 6.7 Cummins Specs 2026 Updated
Quick Answer
The 2015 Ram 2500 6.7L Cummins turbo-diesel produces between 350-370 hp and 660-800 lb-ft of torque, depending on transmission choice. Maximum towing capacity ranges from approximately 16,000 to 17,900 lbs. Always verify these figures against your vehicle’s specific door jamb payload sticker and owner’s manual, as cab configuration, drivetrain, and axle ratios significantly alter your truck’s actual certified capacity.
Finding the exact performance metrics for a 2015 Ram 2500 can be frustrating due to the variety of transmissions and power levels available that year. Many owners confuse standard and high-output configurations, leading to inaccurate expectations for towing and engine longevity. This guide provides verified specs for the 2015 Cummins 6.7L, helping you identify your exact configuration and maintain it for the long haul.
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Start 6 Months FreeThis guide covers 2015 Ram 2500 Heavy Duty configurations equipped with the 6.7L Cummins Turbo Diesel. All specifications are based on factory towing guides and service manuals current as of August 2026. Always verify your specific truck’s capability using the VIN-specific build sheet and the tire/loading information sticker on the driver-side door jamb.
2015 Ram 2500 6.7 Cummins Specs: Official Data Chart
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| Transmission | Horsepower | Torque (lb-ft) | Notes |
|---|---|---|---|
| 6-Speed Manual (G56) | 350 hp @ 2800 rpm | 660 lb-ft @ 1400 rpm | Requires clutch management |
| 6-Speed Auto (68RFE) | 370 hp @ 2800 rpm | 800 lb-ft @ 1600 rpm | Standard duty automatic |
| 6-Speed Auto (Aisin) | 385 hp @ 2800 rpm | 865 lb-ft @ 1700 rpm | High-output configuration |
Horsepower and Torque by Transmission Type
The 2015 6.7L Cummins I6 utilizes a Variable Geometry Turbocharger (VGT) to manage airflow, but the total engine output is capped by the torque-handling capacity of the transmission. While the engine block remains fundamentally the same across all models, the Electronic Control Unit (ECU) calibration changes based on the transmission identified during the startup handshake. This is why the Aisin AS69RC, designed for heavier industrial applications, unlocks the full 865 lb-ft of torque.
Engine Displacement and Compression Ratios
The engine features a 4.21-inch bore and 4.88-inch stroke, totaling 408 cubic inches (6.7 liters). It runs a compression ratio of 16.2:1. This relatively low compression ratio compared to older diesel engines is intentional, aimed at reducing cylinder pressure stress while allowing for higher boost pressures provided by the VGT system.
Towing and Payload Capacity Variables
Towing capacity for the 2015 Ram 2500 is not a single number. It is a derivative of your cab configuration (Regular, Crew, Mega), drivetrain (4×2 vs 4×4), and axle ratio (3.42, 3.73, or 4.10). A 4×2 Regular Cab with a 4.10 rear end will inherently possess a higher maximum towing capacity than a 4×4 Mega Cab Laramie due to curb weight differences affecting available payload.
Understanding 2015 Ram 2500 6.7 Cummins Drivetrain Differences
865 lb-ft
68RFE vs Aisin: Power Delivery Impact
The 68RFE is a six-speed automatic transmission that serves as the workhorse for the majority of Ram 2500 trucks. It utilizes sophisticated torque management software to ensure longevity; when the engine reaches peak output, the ECU will pull timing or limit fuel if the transmission indicates high internal temperatures or slippage. The Aisin AS69RC, however, is a commercial-grade transmission with a higher torque threshold, allowing the engine to operate at peak capacity for longer durations under heavy load.
Why Torque Ratings Differ by Transmission
Torque is the enemy of transmission durability. If you compare the 660 lb-ft rating of the manual G56 to the 865 lb-ft of the Aisin, the gap exists because the manual clutch system and the manual transmission gear sets are limited by the physical size of the components. Ram limits the engine’s output in manual-equipped trucks to preserve the drivetrain’s warranty.
Cummins I6 vs Ford and GM V8 Architectures
The 6.7L Cummins inline-six (I6) engine differs from the Ford 6.7L Power Stroke and GM 6.6L Duramax V8s by prioritizing low-end grunt. The I6 architecture allows for a longer crankshaft, which provides more mechanical leverage at low RPMs. While V8 diesels often chase higher peak horsepower numbers at higher RPMs, the Cummins 6.7 excels in “getting the load moving,” which is why it remains the preferred choice for heavy towing.
Maintenance Protocols for the 2015 Ram 6.7 Cummins Emissions System
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The 2015 model year relies heavily on the Selective Catalytic Reduction (SCR) system. If your DEF (Diesel Exhaust Fluid) level drops below the warning threshold, the vehicle will enter a “limp mode,” eventually restricting vehicle speed to 5 mph until the system is replenished.
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Listen Free for 30 Days- Diesel Exhaust Fluid (DEF): The SCR system injects DEF into the exhaust stream to convert nitrogen oxides into harmless nitrogen and water. Use only API-certified DEF; inferior fluids contain impurities that can crystallize and permanently damage the SCR injector.
- DPF Regeneration: The Diesel Particulate Filter (DPF) collects soot. The truck performs “Passive Regeneration” during highway driving. If you primarily drive in stop-and-go city traffic, you will eventually trigger an “Active Regeneration” cycle, where the engine injects extra fuel to raise exhaust temperatures and burn off the soot. Never interrupt an active regen cycle if possible.
- Common Rail Fuel Injection: The high-pressure common rail system operates at over 29,000 psi. Water or debris in the fuel is catastrophic. Always use a high-quality fuel filter and change it every 15,000 miles to protect the high-pressure fuel pump and injectors.
How to Verify Your Specific 2015 Ram 2500 6.7 Cummins Specs
Visit the official Mopar website and enter your 17-digit VIN. This will generate a factory build sheet listing every option, axle ratio, and transmission code installed at the factory.
For payload and GVWR, rely exclusively on the sticker located on the driver-side door jamb. This sticker is specific to the weight of your truck as it left the assembly line, including all installed options.
Checking Engine Tags for Precise Output
There is a metal data plate located on the side of the engine block, usually on the driver’s side near the front. This tag lists the engine’s serial number, CPL (Control Parts List), and the rated horsepower. Comparing this CPL number against a Cummins dealer database will provide the exact factory-rated performance characteristics of your specific engine block.
When looking for towing capacity, ignore “Maximum Towing” numbers found in brochures. Those numbers often assume a base-model, regular-cab, two-wheel-drive truck with zero options. Use your specific VIN to calculate your true tow limit.
Frequently Asked Questions About 2015 Ram 2500 6.7 Cummins Specs
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Q: Is the 2015 6.7 Cummins engine different from the 2014 or 2016?
A: The engine platform remained largely consistent throughout this period. However, small calibration updates were made to the software to improve emissions efficiency, though the peak torque and horsepower ratings remained stable for the 2015 model year.
Q: What is the most reliable transmission for the 2015 Ram 2500?
A: The Aisin AS69RC is widely considered the most durable choice for heavy-duty towing. It is built to higher industrial standards than the 68RFE, though it does require more expensive, specialized transmission fluid.
Q: Does the 2015 6.7 Cummins have a known “death wobble” issue?
A: While not an engine spec, the 2015 2500 uses a solid front axle design that is sensitive to suspension wear. If you experience steering shimmy, inspect the track bar, ball joints, and steering stabilizer, as these are common wear points for the 2015 chassis.
The 2015 6.7L Cummins performance is dictated largely by the transmission (68RFE vs. Aisin). Emissions systems like the SCR and DPF require consistent, preventative maintenance to avoid costly sensor replacements. Always verify your specific truck’s door sticker for payload and towing limits rather than relying on general brochure data. To confirm your exact factory-rated horsepower and torque, check your VIN-specific build sheet through the official Mopar portal.
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