New engine, aerodynamic improvements and lighter components help improve fuel economy.

With improving fuel economy for the 2013 Ram 1500 pickup at the top of its to-do list, Chrysler Group LLC, Auburn Hills, Mich., did everything from installing a new drivetrain and smoothing out design features to cutting weight and lowering the truck’s stance to meet the goal. The result is a truck that returns 25 mpg on the highway while refusing to sacrifice its workday capabilities.

Representatives from Chrysler’s Ram Truck division spotlighted the changes and gave journalists a chance to sample the updated 2013 model during an August test drive around a test track and through rain-soaked back roads in and around Nashville, Tenn.

The 2013 Ram 1500 gets Chrysler’s 3.6-liter Pentastar V-6 engine as its new base power plant. The engine already is available across the Chrysler lineup but is making its debut in this truck.

While slightly smaller than the 3.7-liter V-6 it replaces, the Pentastar produces 305 horsepower and 269 pound-feet of torque, improvements of 42% and 13%, respectively, over the old engine, said Rick Deneau, head of brands, sales and marketing at Chrysler.