General Motors Corp. says Bob Lutz, currently vice chairman-global product development, will retire at the end of this year, dousing speculation over when the 76-year-old industry maverick might wind down his career.

The move also includes a promotion for one of the auto maker’s key powertrain executives and perhaps foretells a new regime atop GM for the first time in nearly a decade.

Effective April 1, Lutz will assume the newly created role of vice chairman and senior advisor and provide strategic input to GM’s global design and key product initiatives until his retirement. He will continue to report to GM Chairman and CEO Rick Wagoner.

Also effective April 1, Thomas G. Stephens will take Lutz’s role as vice chairman of global product development, but report to Chief Operating Officer Fritz Henderson.

Stephens will retain his responsibility for GM’s global quality, which has improved greatly in recent years. But the auto maker also will restructure its powertrain operations, “to integrate powertrain functional activities into their respective global GM functions.”

As such, Stephens will have responsibility for global powertrain engineering, in addition to global design, product engineering, product planning and program management, the auto maker says.

Powertrain manufacturing will report to Gary Cowger, group vice president of GM Global Manufacturing and Labor Relations. GM will integrate other staffs supporting the powertrain organization into their respective global functions.

The auto maker characterizes the moves as “another important step in GM’s restructuring initiative to create a leaner, more efficient organization.” GM is rapidly shedding jobs, reducing its manufacturing footprint, seeking to eliminate brands, and shifting its product portfolio away from trucks to more fuel-efficient passenger cars while it draws on taxpayer loans to remain afloat.

Lutz’s retirement would presumably signal his departure from the executive offices of a major auto maker, where he has occupied a seat since joining GM in 1963. He held a series of positions at GM Europe before joining the board of management at BMW AG in 1971. Lutz then moved to Ford Motor Co., where he spent 12 years and rose to the position of chairman of Ford Europe and a member of Ford’s board.

Lutz left Ford for the former Chrysler Corp. in 1986, where he made perhaps his greatest mark by bringing to market icons such as the Dodge Viper, Plymouth Prowler and the Jeep Grand Cherokee. The Cherokee helped reshape the automotive landscape, as it and the Ford Explorer fueled the SUV craze.

Lutz rejoined GM in 2001 and immediately injected new life into the global design operations, although it’s only been recently that his signature products have come to market. But they have met critical praise, with the Chevrolet Malibu and Saturn Aura both winning North American Car of the Year honors. Lutz also won critical praise for reamking the Cadillac CTS for its second generation.

“Bob Lutz was already a legendary automotive product guy when he rejoined GM in 2001, and he’s added to that by leading the creation of a string of award-winning vehicles for GM during his time here,” Wagoner says in a statement.

“His 46 years of experience in the global automotive business have been invaluable to us. I’ve personally learned a great deal from Bob and have very much enjoyed the time we’ve worked together,” Wagoner says. “I’m looking forward to Bob’s continued contributions to GM for the remainder of 2009 and I know the impact of his efforts leading GM global product development will continue for years to come.”

Lutz’s announcement comes on the heels of the departure of Tony Cervone, a key executive in the auto maker’s communications department. Cervone held responsibility for communications in each of GM global regions. He left to take a similar role at UAL Corp. parent to United Airlines.

The shake-ups come as GM scrambles to write a viability plan to submit to Congress by Feb. 17. The plan must include concessions from major stakeholders, such as lower wages from the United Auto workers union and capping executive pay at $500,000, for the auto maker to continue receiving government loans.