Updated

The National Highway Traffic Safety Administration is investigating 1 million Ram and Dodge trucks and SUVs for a potential safety defect, after receiving complaints that the vehicles can roll away after being shifted into park.

Fiat Chrysler recalled 1.1 million Jeep Grand Cherokees earlier this year due to a similar issue with a different transmission shifter design. The Jeep problem has been implicated in the death of “Star Trek” actor Anton Yelchin, who was crushed in his driveway by one of the affected vehicles.

The latest investigation covers the 2013-2016 Ram 1500 pickup and 2014-2016 Dodge Durango.

Yelchin, 27, known for playing Chekov in the film series, died in June after his 2015 Jeep Grand Cherokee pinned him against a mailbox pillar and security fence at his home in Los Angeles. His Jeep was among the vehicles recalled in April because of complaints from drivers who had trouble telling if they put the console-mounted shift levers in "park" after stopping. Many reported that the vehicles rolled off after the driver exited. Los Angeles police are still investigating Yelchin's death.

ram transmission handout

(Ram)

In the new investigation, the government says Rams and Durangos have rotary knob shifters that are linked electronically to the transmission. The knobs are turned to the left or right and have detents that click into gear.

But the government said in documents posted Tuesday that it received 43 complaints alleging that the vehicles rolled away unexpectedly. Owners reported 25 crashes and nine injuries. Thirty-four of the owners alleged that the vehicles moved while the shifters were in park, and most said the engines were running.

"Notably, none of the reports indicate that the parking bake was engaged at the time of the rollaway incident," NHTSA said in the documents. Fiat Chrysler says it's cooperating with the investigation, and it joined NHTSA is urging drivers to always use parking brakes when they stop vehicles.

Both Fiat Chrysler shifters are different from conventional levers on the steering column or console. Most cars have console shifters that slide forward or backward to indicate the car's gear. They used to be tied to a cable that physically changed gears. But the auto industry has developed new transmissions with the gear selection controlled electronically.

The Grand Cherokee shift levers like Yelchin's had to be pushed forward or backward to change gears, confusing many drivers. In the recall, Fiat Chrysler changed the software so the vehicles automatically shift into park if the driver's door is opened.

In the latest investigation, no recall has been issued, but one is possible. NHTSA says it's investigating the scope of the problem and how often it happens.

Other automakers also use electronic rotary shifters, but the fact that they're different from conventional shifters seems to confuse drivers. NHTSA on Tuesday posted another investigation into a different automaker's shifters. This time the agency is probing complaints in about 39,000 Jaguar and Land Rover vehicles that also have rotary shift knobs.

In that probe, seven owners complained that the 2012 to 2014 Land Rover Evoque and Jaguar XF rolled away after the driver shifted into park. Four injuries were reported, most while the driver door was open when the vehicles rolled off.

The Associated Press contributed to this report