DETROIT — Kia Motors is recalling more than 70,000 Optima midsize sedans to fix transmission problems that can cause the cars to roll even while they're in park.

The cars are from the 2006 through 2008 model years and were built from Sept. 29, 2005 to June 13, 2007.

In documents filed with the National Highway Traffic Safety Administration, Kia said that on some of the cars, a transmission shifter cable was installed incorrectly and can become detached from the shifter. If the cable comes off, the car would stay in the last gear used even if the driver puts the transmission in park, the documents said.

"If the driver leaves the vehicle without engaging the parking brake, there is a possibility that the vehicle can roll, creating the risk of a crash," Kia said.

No injuries have been reported from the problem, but Kia has concluded that under "extraordinary circumstances" the cars could roll inadvertently.

Kia plans to start the recall this month and will notify owners by mail. Drivers will be told to always use the parking brake when shifting the transmission into park "especially until they can take their vehicle to the dealer," the documents said.

Dealers will inspect the cable and reinstall it if necessary, free of charge.

Owners who have questions can call Kia at (800) 333-4542.