Shortly after Tesla Motor’s CEO Elon Musk published his Master Plan: Part Deux last July, the electric carmaker promoted Jerome Guillen, a former Daimler Truck executive, to VP of the Tesla Semi business unit.

Before joining Tesla in 2010, Guillen was an executive at Daimler’s Freightliner division in Portland, OR where he was involved with that company’s ‘SuperTruck” program.

Now, Electrek is reporting that Tesla has hired several key Daimler engineers who also worked on the same program, including most recently, Evan Chenoweth.

Chenoweth was the lead design engineer of Freightliner’s SuperTruck’s hybrid engine, and is now a Tesla senior mechanical design engineer.

SuperTruck is a U.S. Department of Energy (DoE) initiative that issues millions of dollars in grants to truck manufacturers to increase the fuel efficiency of medium- and heavy-duty trucks by developing new technologies.

Freightliner’s SuperTruck attained 12-MPGe (miles per gallon equivalent) with an 11.0-liter diesel engine paired with an electric motor, which is more than 110 percent better than the average Class 8 truck on the road.

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While most trucks built for the SuperTruck program use hybrid electric powertrains that are far more efficient than the average heavy-duty truck, Tesla wants to take the big step of developing an all-electric semi truck.

In a conference call with analysts last month, Musk said the unveiling of the battery-powered semi should happen in the next six to nine months.

As for production, Musk said, “They should enter production within low single digit years.”

He said he considers anything past 5 years “as infinity.”

To date, Tesla has never made a stated production schedule, and the $35,000, 200-mile range Model 3 will be beaten to the finish line by the Chevrolet Bolt, which arrives before the end of the year.

As for an electric heavy-duty truck, Mercedes-Benz unveiled its 120-mile range HD truck on Monday that is slated for 2020.