WASHINGTON, D.C.: Federal safety regulators have launched a new investigation into Ford's best-selling F-150 pickup trucks after receiving more than 130 complaints about dangerous transmission issues that could lead to sudden deceleration and temporary loss of control.

The National Highway Traffic Safety Administration (NHTSA) said this week it has opened a preliminary evaluation into nearly 1.3 million F-150 trucks from the 2015 to 2017 model years. The issue centers on unexpected downshifting of the transmission into a lower gear without driver input, sometimes while the vehicle is traveling at highway speeds.

In some cases, the rapid downshift has caused the rear wheels to lock or skid, according to complaints filed with the agency.

A Ford spokesperson said the company is "working with NHTSA to support its investigation" and confirmed the probe involves vehicles with six-speed transmissions.

The evaluation follows 138 consumer complaints describing incidents of sudden deceleration. One owner in Ohio reported that their 2016 F-150 shifted from sixth to first gear while driving 70 mph, stating it "nearly threw me through the windshield."

Some owners also reported delays in receiving replacement parts, leaving their vehicles inoperable for extended periods.

NHTSA said there have been no reported crashes or fires but warned that the issue could increase the risk of an accident. The agency will now determine whether to escalate the investigation to an engineering analysis, which could lead to a recall.

This is not the first time Ford has faced scrutiny over similar problems in F-150 trucks. In June 2023, the automaker recalled 668,000 trucks from the 2014 model year for unexpected downshifts that caused control issues or rear-wheel lockups.

Previous recalls include 153,000 trucks from the 2011-2012 model years and an expanded 2019 recall covering 1.48 million trucks in North America, including 2013 models. In another follow-up, Ford recalled 107,000 of those 2013 trucks due to a faulty fix.

Ford's recall record has come under heightened scrutiny. In November, the company agreed to a US$165 million civil penalty after NHTSA determined it had delayed recalling vehicles with faulty rearview cameras.