Revealed at this week's 2009 Chicago Auto Show, the 2010 Dodge Ram Heavy Duty lineup continues its trend toward greater comfort and improved towing prowess -- punctuated by an expressive, big-rig design. Hoping to build upon the momentum generated by its well-received light-duty Ram late last year, Dodge has added a crew cab option (the 2500 crew cab is pictured above) to the HD lineup for the first time, and boasts of improved overall capability and interior upgrades. The HD models will be available in the fall.

With a 90% take-rate, the 6.7-liter Cummins diesel is clearly the Ram HD's most popular engine choice. As such, the Cummins hasn't received any changes and still pumps out an extra stout 650 lb-ft of torque @ 1500 rpm and a peak 350 hp at maximum high-idle speed of 3000 rpm. In an effort to further clean up emissions, a particulate filter has been added to the exhaust system that Dodge claims drops NOX emissions by 90%. The 50-state legal diesel meets 2010.5 emissions standards and requires oil change intervals at 7500 miles. Major overhauls can wait until the odo hits 350,000 miles. Also available is the 5.7-liter HEMI V-8. Updated in 2009, it produces 383 horsepower and 400 lb-ft of torque @ 4000 rpm thanks to an increased compression ratio, active intake manifold and variable valve timing.

Those opting for the diesel have their choice between the G56 six-speed manual and a 68RFE six-speed automatic. A heavy-duty 545RFE five-speed automatic is the sole transmission option on the V-8. Both five- and six-speed automatics include an Electronic Range Select, which allows the driver to limit the highest gear and manual up- and down-shifts. For four-wheeling duties, purchasers can choose between two transfer cases: A manual operable NV271 unit for the ST and Power Wagon and an electric, shift-on-the-fly NV273 case on SLT and Laramie models. Available axle ratios consist of 3.42, 3.73, 4.10 or 4.56.

Passenger space comes in three flavors, but first the regular and crew cab. Storage space abounds in each, from front and rear door panels, to seatbacks and even the floor. A redesigned center console is now large enough, Dodge claims, to store a laptop and provides a power outlet. A lower bin allows for hanging files. Combined, the glove boxes offer 800 cu in. of storage space. And then there's the Mega Cab, which claims the greatest interior space, length and size of anything in class. The cargo volume stands at 72.2 cubic feet; the cab stretches 111.1-in long; the rear-door openings are larger; and the rear seats even recline.