The 2023 Jeep Gladiator EcoDiesel Makes The Case

The 2023 Diesel Jeep Gladiator Overland isn’t quite as fast as its gas-powered counterpart. You can’t get that with a manual transmission or a full-time transfer case. The diesel model also weighs an extra 500 pounds and has a lower maximum tow rating than the gas-powered Sport S Max Tow. The Italian-built 3.0-liter V-6 diesel is louder than the 3.6-liter gas engine, both at idle and at 70 mph. It also adds a total of $4650 to the sticker price and requires fuel that, as of this writing, costs an additional $1.38 per gallon, on average. Oh, and there’s diesel exhaust fluid to think about because running out can leave you stranded. Now allow us to explain why you might want it anyway.

First of all, you will be unique. Most Gladiators are not diesels for reasons that an attentive reader will probably get from the paragraphs above. Additionally, most light-duty trucks no longer offer diesels—Ford discontinued its 3.0-liter Powerstroke for the F-150, Ram discontinued the diesel option from the 1500, and General Motors ditched the Chevy Colorado and GMC Canyon 2.8-liter Duramax in the 2023 redesign. This leaves the trucks the half-ton Gladiator and GM, with their excellent 3.0-liter inline six, as the sole keepers of the oil-burning flame. At least for another year.

If you’re a business owner, going for a diesel Gladiator may have tax advantages thanks to its heavy-duty axles, which top its gross combined weight rating above the 6,000-pound threshold that the IRS believes a real work truck should have. Of course, the same could be said of the gas-powered Rubicons, Mojaves, and Sport S Max Tow models, but we’re just pointing out that the diesel heavy-duty Dana 44 might provide benefits beyond bragging rights. Please consult your CPA — the colossal pumpkin assessor — to see if any of that applies to you. We barely know how to use TurboTax.

But speaking of turbos, the Gladiator’s 3.0-liter V-6 has one, which helps generate 442 pound-feet of torque between 1400 and 2800 rpm. Meanwhile, the naturally aspirated 3.6-liter gas V-6 makes just 260 pound-feet at a relatively stratospheric 4400 rpm. Looking at our test results, the machine seems evenly matched, with the gas Gladiator clocking slightly faster in most contests. But the difference lies in how they get there. The diesel Overland Gladiator accelerates to 60 mph in 7.3 seconds without trying hard. The Gas Gladiator Overland can reach 60 mph in 7.2 seconds, but doing so will require many visits to the peak horsepower of 6400 rpm, an exercise that feels particularly sadistic. The Diesel covered the quarter mile in 15.6 seconds at 87 mph. Which is also a bit delinquent to the gas model, but without the feeling that you’re trying to ride a furious mule down the back of the Breeders’ Cup.

The Diesel is a $4150 option, available in most trims and paired with the 8HP75 heavy-duty transmission more commonly found in the back of the V-8. The 8HP75 is made by ZF in Germany and is a sneaky bargain before 2023, as Jeep adds the same $2000 surcharge applied to the US-built 850RE paired with the 3.6-litre. However, for 2023, the 8HP75 transmission costs $2500, bringing the total diesel spending to $4650. You can’t get the diesel in the base Sport or Mojave, but you can specify it in all the other trims, including the range-topper High Altitude model.

And on the topic of altitude, that’s where the diesel Gladiator will have another advantage over the gas model, thanks to its forced induction. At sea level, the 3.6-liter has the upper hand on horsepower (285 horses to the 3.0’s 260), but drive up to Crested Butte and it will be a different story. Mountain folks—your preppers, off-the-grid hippies, overlanders, fugitives, and hermits—will want diesel, trust us.

Because, on the other hand, diesel offers a longer range even though the fuel tank is smaller. The EPA rates the gas-powered automatic Overland at a combined 19 mpg and the diesel at a combined 24 mpg (28 mpg on the highway). We found the differences to be more extreme, noting the 14 mpg fuel savings observed in the Overland gas and 23 mpg in the diesel. The Gladiator’s 75 mph diesel highway fuel economy results are also impressive at 27 mpg, six better than the gasser. The numbers reinforce the subjective expression that the gasoline engine is hard at work in its day-to-day business, while the diesel is relaxed and content with its role as a truck engine. They also mean that despite the current price difference between regular unleaded and diesel, the oil-fired Gladiator will have to gradually recoup its up-front costs. And we mean really gradual, like beyond 100,000 miles increments, but if the gas vs diesel price relationship returns to where it was a year ago, the Gladiator’s diesel powertrain will pay for itself in less than 60,000 miles (not including the occasional sip of DEF). Or even fewer miles if you tow a lot. Plus, you can use your spark plug budget for the lift kit and larger tires Overland will need to visually offset the wiener-dog proportions.

Now, we mentioned that the diesel Gladiator is noisier at idle and cruising speed, but at wide open throttle, it’s much quieter — 72 decibels to 77 — which again speaks for its comfort. And the sound it makes is cool, if you appreciate the grunt of compression ignition and the whir of the turbocharger working in tandem with a pressurized fuel injection system up to 29,000 psi. It’s the aural signature of a truck you hear before you see, emerging from a blizzard carrying tow ropes and spare cans of fuel like a Saint Bernard with a barrel around its neck.

If you hate the sound, maybe the diesel Gladiator isn’t for you. After all, it’s a convertible body-on-frame pickup truck with solid axles and removable doors. In high-end Overland trim, it’s a caveman in business casual. It’s whimsical, collector’s item, the kind of pet project you’d expect Jeep to launch on its Easter Jeep Safari and then forget about. The Diesel may not be the machine most people get, but it’s what the Gladiator should have.