DETROIT — U.S. sales at Ford and Chrysler last month offered sharply different views on the downtrodden U.S. market for cars and trucks, while General Motors Corp. held its own even though it entered bankruptcy protection. Ford's June sales showed signs of stabilization, as the healthiest Detroit automaker posted its smallest sales decline of the year at 10.7 percent. It also said it gained market share. But Chrysler Group LLC, just weeks after exiting bankruptcy protection, reported a 42 percent drop in sales, hurt by a big cut in fleet sales and declines in all its models except the Dodge Challenger muscle car. GM reported a 33.4 percent sales drop, slightly larger than the 30 percent drop it reported for May before it entered bankruptcy protection. GM plans to sell or close Pontiac, Saturn, Hummer and Saab to focus on four core brands — Chevrolet, Cadillac, GMC and Buick.