The best way to evaluate the 2025 Ram 2500 with the HO Cummins turbodiesel backed with the all-new 8-speed automatic transmission and 3.42:1 axle gears is to use it. You’d probably want to load up a trailer and hit the road for a cross-country trip. Unfortunately, the dealer would surely never agree to it. So I’ll do it for you.
I had the opportunity to get behind the controls of the 6.7-liter Cummins, which belches out 420 horsepower and 1,075 pound-feet of torque without watchful eyes looking over my shoulder. I wanted to see if the truck benefited from the shallower axle ratio and 8-speed transmission featuring deeper first, second and third gears than the outgoing 6-speed truck. The new transmission also enjoys tighter ratios between all the gears to keep the big Cummins in peak power and top fuel economy.
Here’s what I found after towing 42 hours at the helm of the 2025 Ram 2500.
Mile 64: Is the empty trailer still back there?

For the first half of the trip, I was pulling an empty 2,000-pound car hauler. You’d think that you’d feel it behind the 2025 Ram 2500. You don’t. This phrase is often overstated, but it’s true in this case. The only evidence that the trailer is still attached comes from the noisy hitch clatter associated with pulling an empty bumper-pull car hauler.
The new 8-speed transmission allows the use of 3.42:1 axle gears without degrading max towing capacity. Deeper 4.10:1 axle gears are no longer required for max towing and cargo capacity. The advantage is improved fuel economy and drivability. This is especially important for those that like to log miles at higher speeds.
Mile 482: What’s the worst stretch of highway in the U.S.?

I’ve driven all over the U.S., and the I5 through the California central valley is by far the worst in the 48 states. The 18-wheeler-damaged road surface stretches more than 420 miles from Lebec to Red Bluff. It’s also one of the most boring sections of highway, too, and I’ve driven the 850-something miles through the middle of Texas. I’ll say it, at least in Texas you can be fascinated by the sight of dead armadillos on the side of the road. Now, having mentioned all that, I’ve towed this section of the I5 in several vehicles that had the suspension continually bottoming out. The 2025 Ram 2500 handled the cracked and separated freeway like a champ without breaking my back, although the empty trailer took a beating and griped the whole way with its incessant clattering.
Mile 528: Is 20 MPG really possible while towing with a 2025 Ram 2500?

The sweet spot for power and fuel economy of the torquey Cummins appears to be 1,500-1,700 RPM. This translates to 65-75 MPH with the 3.42:1 axle gears and 0.67:1 overdrive gear in the ZF 8-speed transmission. If you can stand to keep the speeds below 65 MPH and the engine RPM below 1,500, you’ll be rewarded with significantly better fuel economy. After experimenting with speeds in the flats of Central California, I think it’s possible to squeak out 20 MPG pulling an empty trailer in the right conditions. Of course, it would require a really flat highway and no headwind along with the sub 65 MPH speeds. I hope someone tries it and comments if it’s possible. Overall, I really appreciated the MPG and 31-gallon fuel capacity delivering a 500-mile plus range.
Mile 979: How does lane sense work with a trailer?

The Ram Lane Sense takes some getting used to. It recognizes the length of your trailer and monitors if the trailer tires are staying in the lane. When you cross a painted line, the system notifies you with a small vibration and pull in the steering wheel along with subtle lights on the dash. If you’re more of an analog driver that can’t be bothered with nanny technology, you can simply turn the system off.
Mile 1,417: How much can the 2025 Ram 2500 tow?

My dad lives at the northern most end of Washington state and no longer had a use for his compact Kubota tractor, so I felt compelled to adopt it. Once I arrived in Washington I loaded the 2,436-pound tractor on my trailer for a total towed weight of 4,436 pounds, which is far less than the 19,890 pounds this truck is rated for. Once again, I hardly noticed the added weight. However, I didn’t hear the trailer hitch rattling anymore. There was now plenty of tongue weight to keep it from complaining.
Mile 1,511: Can the exhaust brake significantly reduce brake wear?

The factory 2025 Ram 2500 exhaust brake is amazing. There are two settings. The full setting is more aggressive than the auto setting. Full setting engages the exhaust brake any time you decelerate, while the auto setting appears to only apply the exhaust brake when the brakes are applied. With my relatively small trailer load the full exhaust brake nearly eliminates the need to apply the traditional brakes on the highway. This will surely increase the overall life of the brakes.
Mile 1,728: Will the 2025 Ram 2500 get you stuck in a parking lot towing a trailer?

I absolutely love the turning radius and maneuverability of the crew cab short bed 2025 Ram 2500, which is extremely helpful when pulling a trailer through fuel stations, crowded rest stops and fast food parking lots. I was able to easily weave in and around tight spots and inconsiderate drivers without clipping the trailer tires on curbs. The power telescoping memory mirrors offer much better rear visibility than some of the side mirrors used by Ram in the past.
Mile 1,845: Couldn’t you pull that trailer load with a 1/2-ton truck?

Of course, this trailer could be pulled by a much smaller gas truck, but it would not be as comfortable of a towing experience. Aggressive drivers that refuse to endure the sluggish performance of a 1/2-ton truck towing a trailer will appreciate the overall performance of the 2025 Ram 2500 with the 8-speed transmission behind the Cummins diesel engine. Pulling a heavy trailer tens of miles a day is far different than towing it hundreds of miles a day.
Mile 2,384: Will adaptive cruise control make your life easier, increase MPG?

Adaptive cruise control is now standard for 2025 on the Ram 2500. It’s a nice feature on a 3/4-ton, although in this case, it’s a little bit clunky when changing lanes. The system wants to accelerate and slow down too quickly. I feel like it could benefit from longer adjustment range options, especially when towing heavier loads. I used the adaptive cruise control where I could and averaged a total of 15.7 hand-calculated MPG for the entire trip, however I think the 3.42:1 axle gears and 8-speed transmission are the real reason these numbers were possible.
Our take: When is a 1/2-ton truck no longer enough when towing?

Some modern 1/2-ton trucks have tow capacities up to 14,000 pounds. I assure you that it’s not something you’ll want to do for an extended period of time. I regularly punish myself by towing 4,000-5,600 pounds behind gas V-6 and V-8 engines. Towing any amount of weight with a large diesel engine vehicle, such as the 2025 Ram 2500, is a much more stress-free experience when compared to a gas engine vehicle. The grunty low-engine RPM of the diesel is soothing when compared to a screaming high-RPM gas V-6 or V-8 and the braking system is vastly superior to a smaller tow rig. A 3/4-ton truck is simply a much more stable platform to tow from. In my opinion, if you regularly tow more than 5,000-7,000 pounds long distances, especially through mountainous terrain, you should probably be doing it in a 3/4- or 1-ton truck.







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