Tesla executive Jerome Guillen has left the electric car manufacturer after more than a decade.

Guillen has held various roles at Tesla reporting directly to Elon Musk since November 2010 and prior to his appointment as the president of the carmaker’s Heavy Trucking unit in March, he had served as president of automotive operations and program management since 2018. He was considered as number two behind Musk at Tesla in the automotive side of its business, Electrek writes.

Guillen established himself at Daimler’s truck division Freightliner and oversaw the development of a new generation of Class 8 trucks. When he first joined Tesla, he was the program director for the Model S and led its production ramp-up.

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Tesla announced Guillen’s departure in a recent SEC filing.

“As of June 3, 2021, Jerome Guillen, President, Tesla Heavy Trucking, of Tesla, Inc. (“Tesla”), departed Tesla. We thank him for his many contributions and wish him well in his future career,” the automaker wrote.

Neither Tesla nor Guillen himself has publically stated just why he is leaving the car manufacturer.

Guillen’s departure comes before Tesla has delivered a single Semi, an all-electric truck that was unveiled in November 2017. Deliveries of the Tesla Semi were originally set to begin in 2019 but a few months ago, Musk revealed that due to battery cell constraints, deliveries are “probably ok next year.”

Opening image via WikiMedia Commons / Heinrich-Böll-Stiftung