2015 Ram 2500 6.4 Hemi Specs: Full Engine and Towing Chart

The 2015 Ram 2500 with the 6.4L HEMI V8 makes 410 horsepower at 5,600 rpm and 429 lb-ft of torque at 4,000 rpm, straight from the factory spec sheet. It sits between the standard 5.7L HEMI and the optional 6.7L Cummins Turbo Diesel in the 2015 lineup, offering more grunt than the base gas engine without diesel maintenance costs.

Below is the full engine breakdown, the official towing and payload charts by axle ratio, and the issues 2015 6.4 Hemi owners actually report at higher mileage.

6.4 Hemi Engine Specs For The 2015 Ram 2500

Officially, the 6.4L HEMI in the 2015 Ram 2500 is rated at 410 hp at 5,600 rpm and 429 lb-ft of torque at 4,000 rpm. It displaces 6.4 liters (392 cubic inches) from a bore of 4.09 inches and a stroke of 3.72 inches, running a 10.0:1 compression ratio in this truck application. That compression figure is lower than the 10.9:1 used in the SRT passenger-car version of the same engine family, a detail several older spec sheets get wrong by quoting the SRT number instead.

The engine uses Chrysler’s Multi-Displacement System, or MDS, which shuts down four cylinders under light throttle to save fuel, then reactivates all eight under load. Oil viscosity matters here. Ram’s own documentation calls for 0W-40 full synthetic in the 2500/3500 application, and 2015 owners running the correct spec report fewer MDS-lifter complaints than those who substitute a lighter Ram 1500 oil weight. For maintenance reference, check the 64 Hemi oil filter location guide before your next change.

How The 6.4 Hemi Compares To 5.7 Hemi And Cummins

Parked next to its two engine siblings, the 6.4 Hemi’s role in the 2015 lineup becomes clear. It is the middle option, built for buyers who want more capability than the base gas engine without taking on the Cummins price tag or diesel emissions hardware.

The 6.4 runs on regular 87 octane gasoline, unlike some owners’ assumption that it needs premium fuel. For a broader side-by-side of how the 2500 stacks up against its half-ton sibling, see the Ram 1500 vs Ram 2500 specs comparison.

2015 Ram 2500 6.4 Hemi Towing Capacity By Axle Ratio

Ram publishes exact towing numbers by axle ratio, not just one headline figure, and the gap between them is significant. These are SAE J2807-compliant figures for a 2015 Ram 2500 crew cab with the 6.4L HEMI, straight from Ram’s official towing guide.

Stepping from 3.73 to 4.10 gears adds roughly 3,000 pounds of GCWR and around 3,000 pounds of extra max trailer weight on the same engine and axle. Regular cab, Mega Cab, and 4×4 configurations shift these numbers slightly, so always confirm against the door jamb sticker or Ram’s official 2015 towing chart for your exact build. For the full year-by-year Ram 2500 breakdown, see the Ram 2500 towing capacity guide.

2015 Ram 2500 6.4 Hemi Payload Capacity And GVWR

Max payload for the 2015 Ram 2500 6.4 Hemi runs up to 4,450 pounds on 4.10 gears, tied to a 10,000-pound GVWR. Payload is calculated as GVWR minus the truck’s base curb weight, so heavier cab configurations and added options reduce the number below the maximum rating.

Ram’s own chart language treats payload and max trailer weight as mutually exclusive figures. In practice, that means a truck loaded near its payload ceiling should not also be pulling near its max trailer rating at the same time, since combined weight is capped by GCWR rather than either figure alone. For exact per-configuration numbers, cross-reference the Ram 2500 6.4 Hemi specs pillar page, which covers payload spread across model years.

Common Problems Owners Report With The 2015 6.4 Hemi

Spec sheets do not show what 2015 6.4 Hemi owners actually deal with at higher mileage. Three issues come up repeatedly across owner forums and repair records for this specific engine and year.

• Electronic throttle service warnings in cold weather. Owners report a red lightning bolt indicator and sluggish throttle response during cold starts, often tied to sensor or wiring corrosion in the electronic throttle control system.
• MDS lifter tick. The 6.4’s angled lifter design can starve for oil under certain conditions, producing a ticking noise some owners resolve with an MDS delete kit, a workaround rather than a factory fix.
• 66RFE transmission complaints. Multiple 2014 to 2015 owners report shudder or delayed engagement into reverse, with some units needing a rebuild in the 40,000 to 90,000-mile range.

Consumer Reports rates the 2015 Ram 2500 below average for overall reliability, with the transmission flagged as a notable trouble spot in owner surveys. For a deeper breakdown of these patterns across model years, see the Ram 6.4 Hemi problems guide.

Is The 6.4 Hemi Worth It In A 2015 Ram 2500

The 6.4 Hemi works as the gas middle ground in the 2015 lineup, giving up some torque and fuel economy compared to the Cummins in exchange for a lower purchase price and no DEF, DPF, or EGR maintenance. The EPA does not publish fuel economy ratings for heavy-duty trucks in this class, but owner-reported real-world mileage on forums like RamForumZ and DodgeTalk runs roughly 11 to 17 mpg unladen, depending on gear ratio, driving style, and terrain. Towing drops that figure into the single digits to low teens on steep grades.

What The 2015 Ram 2500 6.4 Hemi Numbers Mean For You

The 2015 Ram 2500 6.4 Hemi makes 410 hp and 429 lb-ft, and its towing capacity swings from 19,800 to 22,800 pounds GCWR depending entirely on axle ratio. Payload tops out around 4,450 pounds on the same 4.10 gearing that maximizes tow rating. Axle ratio, not just engine choice, is the deciding factor for how much this truck can pull. Before hitching up near the max figures listed here, check the door jamb sticker or run the VIN through Ram’s site to confirm the exact rating for your specific truck.

Frequently Asked Questions About The 2015 Ram 2500 6.4 Hemi

How much horsepower does the 2015 Ram 2500 6.4 Hemi have?

The 2015 Ram 2500 6.4L HEMI produces 410 horsepower at 5,600 rpm and 429 lb-ft of torque at 4,000 rpm. This is a naturally aspirated V8 with a 10.0:1 compression ratio in the truck application.

What is the towing capacity of a 2015 Ram 2500 with the 6.4 Hemi?

Towing capacity ranges from 19,800 lb GCWR on 3.73 gears up to 22,800 lb GCWR on 4.10 gears. Max trailer weight runs from roughly 12,480 lb to 16,120 lb depending on the exact configuration.

Is the 6.4 Hemi reliable in the 2015 Ram 2500?

Consumer Reports rates the 2015 Ram 2500 below average for reliability, with the 66RFE transmission as the most-flagged trouble spot. The engine itself is generally durable, though MDS lifter tick and cold-weather throttle faults are common owner complaints.

What is the difference between the 5.7 and 6.4 Hemi in a 2015 Ram 2500?

The 5.7L HEMI makes 383 hp and 400 lb-ft, while the 6.4L HEMI makes 410 hp and 429 lb-ft with a higher tow and payload rating. Both use the same 66RFE 6-speed automatic and run on regular 87 octane fuel.

What is the payload capacity of a 2015 Ram 2500 6.4 Hemi?

Payload capacity runs up to 4,450 pounds on a 10,000-pound GVWR, depending on axle ratio and cab configuration. Actual payload drops as options and cab weight increase above base curb weight.