FRANKFURT -- Daimler trucks chief Wolfgang Bernhard, a maverick manager once seen as a successor to CEO Dieter Zetsche, has made clear he does not want his contract extended, German magazine Der Spiegel said.

Bernhard's contract is due to expire in February 2018. Daimler declined to comment.

Spiegel said supervisory board members, who were going to discuss extending Bernhard's contract at a meeting on Friday, were surprised to learn that Bernhard, 56, would not stay on if offered an extension, Der Spiegel said, citing unidentified company sources.

Bernhard's skills as a turnaround manager landed him top divisional jobs such as head of Mercedes-Benz cars, Chrysler and as CEO of the Volkswagen passenger car business in a wide ranging career in the auto industry.

But last year Daimler extended Zetsche's contract by three years, a move that effectively ruled out Bernhard as a potential successor.

Bernhard will be close to 60 in 2019 when Daimler is due to choose its next chief executive.

In February last year, Daimler also promoted Ola Kaellenius, a 46-year-old Swede, to become board member for r&d, a move that company insiders say made him a natural heir to Zetsche.