Freightliner Custom Chassis Corp. is completing final testing of pre-production S2G propane autogas trucks and expects to begin production of the vehicle in the summer, according to a company spokesperson.

Freightliner, which introduced the front-engine truck at the 2013 NTEA Work Truck Show, has built 25 pre-production S2G trucks so far. The company is now evaluating the systems of four test vehicles.

"Once we've reached a level of confidence with these four test vehicles, we will being delivering the field test units to assigned customers," according to Freightliner. "Our expectation is to revue real-world, operational and positive feedback from end users. When we do, we will then schedule regular production and begin taking orders."

The S2G will offer an 8.0L dedicated propane autogas engine that generates 339 hp and 495 lb.-ft. of torque, mated to an Allison 2300 automatic transmission. Gross vehicle weight will come in at 33,000 pounds.

The S2G utilizes the Freightliner M2 cab, which features a sloped, forward-tilting hood for improved visibility and engine access.