Ford Motor Co. said sales fell 0.3 percent in the month to 191,529 cars and light trucks. Sales of light trucks at Ford fell 5.4 percent, while car sales rose 8.8 percent.
At General Motors Corp., U.S. sales fell 1 percent to 221,192 compared with May 2010. GM sold 98,027 cars and 123,165 light trucks in May.
Chrysler sales rose 10.1 percent, Autodata reported. Sales of Chrysler cars fell 4 percent, but light truck sales rose 16.7 percent, Chrysler reported.
Sales of imports were mixed with Volkswagen Group of America Inc. sales up 24 percent and Toyota sales off 33.4 percent in the month.
The earthquake and tsunami in Japan did considerable damage to key parts suppliers, not only for Japanese brands, but for U.S. brands that rely on parts from Japan. As inventories of vehicles were tight, automakers slowed down discounts, which put the brakes on sales.