Automakers General Motors, Chrysler and Toyota on Thursday scored US sales gains in April, extending the rebound from bad winter weather, while Ford sales unexpectedly slipped. GM, the largest US automaker, said total sales rose 7.0 percent in April from a year ago, to 254,076 vehicles. Chrysler Group, the US unit of Italy's Fiat Chrysler Automobiles, clocked in a 14 percent jump year-over-year with 178,652 vehicles sold, its best April performance since 2007. For General Motor Company and Chrysler, sales gains were higher than estimates of 4.7 percent and 12.30 percent, respectively, from analysts at Edmunds. com, a car-shopping website. Ford Motor Company, the number-two US automaker, reported sales fell 1.0 percent from a year ago, to 141,950 vehicles. Edmunds.com analysts had forecast a 4.6 percent increase. Ford's disappointing sales numbers came the same day the company announced its chief executive Alan Mulally will step down on July 1 and named chief operating officer Mark Fields to replace him. Japanese rival Toyota, the world's top automaker, said US sales increased 9.0 percent to 199,660 vehicles. "Sales momentum from March rolled into April pushing the industry to its best back-to-back monthly sales pace since fall of 2007," said Bill Fay, Toyota division group vice president and general manager. Fellow Japanese automaker Nissan said US sales shot up 18.5 percent to an April record of 94,764 vehicles. Overall, US auto sales in April are expected to have extended their spring rebound after unusually harsh winter weather in January and February hammered sales. Edmunds.com predicted a 9.1 percent rise in US auto sales in April following the 5.7 percent gain in March. Kurt McNeil, GM's US vice president of sales operations, was upbeat about demand. "The economy continues to strengthen," he said in a statement. "Retail demand was steady in April, and truck sales and transaction prices were especially strong."