Allison Transmission has announced long-standing chairman and CEO Lawrence Dewey will stand down next year after a career spanning more than four decades.

Dewey is the longest-serving head of Allison and was responsible for the transition from being part of General Motors to the public company it is today and has served as CEO since 2007.

He will stand down on 31 May, 2018 when his new employment agreement concludes and retire. It is believed the board will consider both internal and external candidates in its search for a new CEO.

“We are extremely thankful for Larry’s dedicated leadership and we respect his request to retire,” said Thomas Rabaut, lead director of the board and chairman of the Nominating and Corporate Governance Committee for Allison.

“He has successfully guided Allison through several periods of significant change and positioned it well for the future. We are confident that the transition plan will be well executed.”

Dewey said he would work closely with the board as his tenure comes to a close.

“As Allison enters its second century I’m energised about the opportunities that lie ahead for this great company and its talented employees, both in the U.S. and around the world,” he said.

“Over the next 18 months, I plan to work closely with the board to ensure a smooth and successful transition of the company’s leadership.”