Ford’s dependence on truck sales was demonstrated last month when the Dearborn, Michigan, automaker said Tuesday May sales dropped on “tight supply” of its latest versions of the extremely popular F-150 pickup truck. Ford’s sport-utility-vehicle sales were also down despite strong demand for the recently introduced and much-improved second-generation Ford Edge midsize crossover.

“We continue to see strong consumer demand for our newest products, including Edge, F-150, Mustang, Transit Vans and Lincoln MKC,” Mark LaNeve, the company’s head of U.S. sales, said in a statement.

The new, wider, lower, sixth-generation 2015 Ford Mustang that went to showrooms in November pushed deliveries of the iconic muscle car nearly 40 percent to 13,616. The Ford Fiesta mini was another notable gainer at 31 percent to 9,426.

Ford utility vehicles eked out a slight gain but saw significant drops in key models, like the Ford Escape, which has been out in its present form since 2012. Ford has chosen the 2016 Escape and the 2016 Fiesta to be the first to receive its Sync 3 infotainment system in a bid to lure buyers with what it says is a much improved version of its dashboard computer interface.

Ford’s luxury Lincoln division gained nearly 4 percent on demand for the Navigator full-size Luxury SUV, which was refreshed in the 2015 model year to compete better against the Cadillac Escalade and Infiniti QX 80. Truck sales dropped 5 percent last month despite an 8 percent gain in the Ford Transit Connect vans. Production of the new F-150, which carries a lighter, rust-free aluminum frame, has been constrained for months as the company worked to get the two factories set up to make the truck.

The plant in Dearborn is fully operational, but the Kansas City, Mo., assembly site only came completely online this quarter, the company said. A recent shortage in truck frames has also impacted supply, the Wall Street Journal reported.