Vehicle production in North America in May fell 2.4 percent from April and dropped 6.4 percent from the year-ago month.
May output totaled 1,392,251 units; cars accounted for 53.4 percent, and trucks comprised 46.6 percent.
Last week's North American car and truck production was estimated at 334,830 units, 14.7 percent above the prior week but 4.3 percent below the year-ago week.
So far this year, 7,112,546 vehicles have been assembled in the United States, Canada and Mexico, 2.3 percent above the year-ago period.
General Motors' Arlington, Texas, assembly plant resumed operations after a six-month change-over from cars to trucks. The plant now assembles Chevrolet C/K and GMC Sierra full-sized pickups and the Chevrolet Tahoe and GMC Yukon full-sized sport-utilities.
The company's Pontiac East truck plant remains idle because of a UAW strike that began April 21.
The Mazda B-series pickup line is down for changeover at Ford Motor Co.'s Edison, N.J., plant. Ford Ranger assembly continues there.