North American automakers produced 1,390,175 light vehicles in September, a 13.5% gain from same-month 2012.

Last month’s total included 598,777 cars,  up 4.4% from last year. All segments recorded gains except small cars, which dropped 4.9%.

Light-truck production jumped 21.4% to 791,398 units. Gasoline prices have fallen over the past three months, which typically lowers consumer interest in smaller, more fuel-efficient vehicles. Also, as the fourth-quarter normally is a high-volume period for pickups and SUVs, manufacturers are focused on maintaining a large supply of light trucks.

Nissan had the biggest year-over-year growth among the top manufactures, up 36.4%, resulting primarily from a surge of light-truck output from its U.S. plants. At the end of August, U.S. inventory of Nissan’s domestic light trucks was down from the prior month and year-ago. The automaker’s robust September production helped boost its light-truck stock 15.2% above the August figure.

The Detroit Three produced 782,692 LVs. Ford built 260,342, up 10.7%. WardsAuto estimates General Motors made 297,927 units, increasing 16.8% from same-month 2012.

Chrysler recorded its first year-over-year gain since June, climbing 22.2%, to 224,423 units. While the automaker’s September car production fell 10.8%, light-truck output soared 39.4%.

September production in the U.S. rose 22.2% from 2012, to 941,246. Year-to-date, 8,092,538 LVs were built, a 6.7% gain over last year.

Mexican plants produced 3.4% fewer LVs compared with last year, with a total of 238,785. January-September output reached 2,216,963 units, up 3.5%.

Canada’s September production of 210,144 was 1.3% above year-ago. However, its year-to-date total of 1,755,657 units was down 5.4% from 9-months 2012.

September’s output lifted the North American year-to-date tally 12,065,158 units, 4.2% above like-2012.