GM Vice Chairman Bob Lutz, an executive credited with bringing an urgency to the automaker's efforts to revamp its vehicle line-up and shake off negative consumer perceptions, will retire on May 1, General Motors Co said on Wednesday.

Lutz, 78, had been serving as a senior adviser to GM Chairman and Chief Executive Ed Whitacre after shelving retirement plans to take charge of the automaker's marketing after it emerged from bankruptcy in July 2009.

An outspoken executive who both challenged global warming and championed GM's all-electric Volt, Lutz is credited with revitalizing GM's product development efforts after being hired by former GM CEO Rick Wagoner in 2001.

With the departure of Lutz, all of the senior executives at the helm of GM in the run-up to its U.S. government-funded bankruptcy will have left the company.

During a 47-year career in the auto industry, Lutz had also been a senior executive at Chrysler Corp, Ford Motor Co and BMW.

The announcement comes a day after GM shook up its sales and marketing operations in its home market for the third time in five months.

Lutz was charged with overhauling GM's marketing efforts under former CEO Fritz Henderson, but he appeared to have been sidelined by Whitacre, a former AT&T executive brought in by the Obama administration.

In late February, Whitacre named Stephen Girsky, a former investment banker, as special adviser and vice chairman in charge of corporate strategy, a move that raised questions about the tenure and role of Lutz.

Lutz had said he wanted to inject passion and a renewed attention to detail in GM's car designs. Some of the vehicles he shepherded through the development process, such as the Chevy Malibu, have been credited with making the automaker competitive in the market for passenger cars again.

But a plan to revive the Saturn brand with European-inspired designs fizzled and the automaker recently dropped plans to produce another vehicle that Lutz had backed: the Cadillac Converj, a luxury electric car.

FROM VIPER TO VOLT

A cigar-smoking former fighter pilot and collector of military jets, Lutz was associated with high-horsepower performance cars through his career and oversaw the development of the Dodge Viper during his stint at Chrysler.

But at GM his biggest splash was the development of the Volt, a plug-in electric car scheduled to roll out later this year that became a cornerstone of GM's effort to reinvent itself and show it could compete on hybrid technology.

In 2006, Lutz assembled a team of engineers and designers to develop the concept version of the Volt that the automaker showed off at the 2007 Detroit auto show.

The goal, Lutz and others involved in the project have said, was to create an environmentally friendly halo car that would challenge the prestige of the market-leading Prius hybrid from Toyota Motor Corp. <7203.T>

The Volt was once again to change perceptions about Chevrolet and in the larger sense, GM, leapfrogging the technology leader, Toyota, Lutz said last week.

Nicknamed Maximum Bob for his larger-than-life persona in the auto industry, Lutz had raised eyebrows and earned a quiet reprimand from Wagoner when in February 2008 when he dismissed global warming as a total crock of shit.

He later said that his personal views had no bearing on GM's commitment to build environmentally friendly vehicles.

Lutz also courted controversy with his criticism of U.S. government mandates for higher fuel efficiency, known as the CAFE standards. Lutz said the government was wrong to tell manufacturers to make more fuel-efficient cars without taking unpopular steps to tax gasoline.

That's like fighting obesity by telling clothing manufacturers they can produce only small sizes, Lutz told reporters at the 2008 Detroit auto show.

Lutz said his late-career conversion to electric-drive technology, which made him an unlikely darling of environmental advocates, reflected his belief GM needed to take risks to change consumer perceptions.

I embrace whatever it is that is unusual and apt to change people's perceptions, Lutz said. You have to do something outrageous. Little, tiny adjustments are not going to do it. You've got to get out there and stun them into a new awareness.

On the sidelines of the Geneva auto show this week, Lutz said he had considered retirement last year out of frustration with the potential for government interference with GM.

But he said that more recently he had begun to think about leaving GM because he felt he had accomplished what he had set out to do nine years before. I honestly feel I can look back with satisfaction and say the team I was privileged to lead in product development has actually achieved more than what I would have hoped for, Lutz said.

(Additional reporting by Soyoung Kim in Detroit and David Bailey in Geneva, Editing by Maureen Bavdek, Steve Orlofsky and Matthew Lewis)