<div><p>DETROIT (Reuters) - General Motors Co <GM.UL> has replaced the head of its mass-market Chevrolet brand as the management shake-up continues at the top U.S. automaker.</p><p>Brent Dewar, a 31-year GM veteran, will retire in April 2010 and serve out the remainder of his career as an adviser to the newly appointed head of North American operations, Mark Reuss.</p><p>Dewar, who had introduced fuel-efficient GM models at last week's Los Angeles auto show, will be replaced immediately as head of Chevrolet by James Campbell, a 45-year-old executive who had previously headed Chevrolet's fleet sales operations.</p><p>The change comes at a time of tumult in GM's executive ranks as executives who devoted a full career to the Detroit-based automaker find themselves being shown the door.</p><p>The Chevrolet appointment is especially crucial because GM expects the brand to carry the burden of driving sales and market share as it sheds Hummer, Saab, Saturn and Pontiac.</p><p>Dewar, who previously headed GM sales in Europe, had been appointed to lead Chevrolet in July as the automaker emerged from bankruptcy after taking $50 billion in government aid.</p><p>Dewar had been appointed by former GM Chief Executive Fritz Henderson, who resigned last week in a split with the automaker's board led by Ed Whitacre.</p><p>The Obama administration dismissed Henderson's predecessor, Rick Wagoner, in March after he resisted calls to consider a restructuring in bankruptcy.</p><p>Henderson had vowed to shake up GM's insular and slow-moving decision-making process, but resigned after eight months on the job when the automaker's board decided to push for faster changes under new leadership.</p><p>GM Chairman Whitacre, who also became acting chief executive with Henderson's departure, said this week that the new team of GM executives would not have long to show results.</p><p>The automaker is on the verge of hiring a new chief financial officer, Whitacre said this week.</p><p>(Reporting by Kevin Krolicki, editing by Leslie Gevirtz)</p><img src="http://admatch-syndication.mochila.com/images/ad.gif?aid=65119947&bid=informcom" /></div><div id="copyright"><div>

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