The Big Three automakers posted mixed results for May, even as Detroit continued to use incentives to lure customers to the showroom.

While General Motors ( GM) posted a gain of 4% over May 2002's sales, Ford's ( F) sales were down 0.7%, and DaimlerChrysler's ( DCX) U.S. sales sank by 3%.

Car sales were down across the board. GM's car sales fell 7% to 177,330 vehicles from last year's 183,566, but its truck sales grew 13% to 258,165 from last year's 219,470.

A 13% decline in car sales at Ford offset a 7.5% gain in truck sales. DaimlerChrysler's car sales were 5% below last year, and truck sales fell 3%.

Despite its gains, GM lowered its second-quarter U.S. production plan to 1.37 million vehicles from 1.39 million vehicles, citing tornado damage at its Oklahoma City plant. The world's largest automaker predicted third-quarter production would be 6% lower than last year's level at 1.225 million vehicles.

Ford plans to trim third-quarter production to 810,000 vehicles from 951,000, but it reiterated its earnings estimates for 2003, saying that it is on track to earn 70 cents a share this year. Ford plans to increase production in the second quarter by 10,000 vehicles.

GM said it will continue its zero-percent financing program through July 7 and will now offer cash rebates worth as much as $4,000.

Last week Saul Rubin, an analyst at UBS Warburg, predicted that one of the Big Three may end up having to file for Chapter 11 in the distant future if trends continued.

GM's shares lost 39 cents to $35.95. Ford dropped 38 cents to $10.69, and DaimlerChrysler dropped by 11 cents to $31.65.