Peterbilt has rolled out new medium- and medium-heavy duty trucks that are replacing earlier vehicles and will soon be built with EPA-2010 diesels.

They are the Model 337, a Class 7 truck or tractor that succeeds the 335, and the Model 348 "heavy 7" truck that succeeds the Model 340. They join the lighter 325 and 330 models in the builder's midrange lineup.

The Model 337 is rated at 26,000 to 33,000 pounds and is designed for P&D, beverage and food service delivery, and public utility applications. Customers can choose between the Cummins-built Paccar PX-6 and PX-8 engines rated from 200 to 360 horsepower. Allison automatics or Eaton Fuller 5- and 6-speed manual transmissions or available, as are several front and rear axle options and suspensions. A hybrid version uses Eaton's diesel-electric drivetrain with a 240 horsepower PX-6.

The Model 348 is rated at 35,000 to 66,000 pounds and is intended for more rugged applications like construction, petroleum delivery, trash, and heavier public utility tasks. It comes with the PX-8 diesel and many drivetrain and chassis options, including single- or tandem-rear axles. Power take-offs can be driven from the front or rear of an engine, and front frame extensions are optional.

The new models are now being built at the Ste. Therese, Quebec, plant operated by Paccar Inc., Peterbilt's parent. EPA-2007 diesels are now being installed in trucks titled as 2010s. Workers are preparing to begin installing 2010-legal diesels with selective catalytic reduction beginning in early January, and these trucks will be titled as 2011s.

Like other Peterbilt conventionals, the 337 and 348 use an aluminum cab that claims light weight, ruggedness and resistance to corrosion. The new models get doors with slightly lower window sills for better visibility to either side. As before, a large rear window and two-piece flat-glass windshield are standard while curved rear-corner glass windows are optional. Model 348s are available with steel structural reinforcements for on/off-road severe service.

A redesigned interior for both models includes an "in-mold" process that imbeds the color permanently into the material, preventing peeling, scratches, scuffs and fading that can occur in harsh environments. A new driver information display shows key vehicle performance data and indicator-warning icons, while backlit gauges are easy to read and understand. The cab also has a new HVAC system for improved air flow.

Dash panels are removable, providing easy access to electrical and HVAC components. A new multiplex electrical system simplifies wiring behind the dash and facilitates troubleshooting. The new models are available with a GPS navigation system that's built into the dash. A new door pad design features power windows, mirrors and lock switches. The cab is standard with dual cup holders.