The company reported a 1.8 percent increase in truck sales.
Truck sales were 234,848, down less than a percent from the record level of June 1998.
For the first three months of this year, light truck sales were down even more, to 53.8 percent.
Its total car and truck sales fell 23.7 percent for the month.
And its truck sales, while still small, have more than doubled.
The sales of light trucks declined 7 percent in the month.
Overall truck sales at Ford were down 17.9 percent, the company said.
The latest: sales of cars and light trucks were up 12 percent in May.
The sales of light trucks rose by 22.8 percent, to 101,539, in the 10-day period.
The problems for the Japanese companies come at a time when truck sales are growing in numbers and diversity.