The Rubicon has slightly lower ratings.
After introducing the EcoDiesel V6 to the Wrangler last year, buyers of the Gladiator gain access to the mill for the 2021 model year. The newly available EPA fuel economy ratings indicate the diesel-powered truck returns 22 miles per gallon city, 28 mpg highway, and 24 mpg combined. For the more rugged Rubicon, the figures fall slightly to 21 mpg city, 27 mpg highway, and remain at 24 mpg combined.
For comparison, the same mill in the 2021 Wrangler Unlimited has an EPA fuel economy rating of 22 mpg city, 29 mpg highway, and 25 mpg combined. Again, the Rubicon is slightly less efficient at 21 mpg city, 26 mpg highway, and 23 mpg combined.
Gallery: 2020 Jeep Gladiator Rubicon: Rubicon Trail
The 3.0-liter EcoDiesel V6 produces 260 horsepower (194 kilowatts) and 442 pound-feet (600 Newton-meters) and comes exclusively with an eight-speed automatic in the Gladiator and Wrangler. Models with this powerplant get tougher Dana 44 axles at the front and rear that are generally for the Rubicon grade of the gas-fueled examples.
The Gladiator EcoDiesel in the Sport and Overland grades uses the Command-Trac part-time four-wheel-drive system with a 2.72:1 low-range gear ratio. Opting for the Rubicon gets buyers Rock-Track part-time 4WD with a 4.0:1 low-range ratio.
The 2021 Gladiator with the EcoDiesel goes on sale in the third quarter. Jeep isn't yet discussing pricing for the diesel-powered truck. A rumor puts the starting figure above $40,000, and the Rubicon could begin at $51,370. It's not yet clear whether the new Mojave would be available with the diesel. As a guide, the powertrain adds $6,000 to a Wrangler, which includes $4,000 for the engine and $2,000 for the mandatory eight-speed automatic.