Regulators received over 100 consumer complaints about transmission shifting to a lower gear without warning. The investigation affects some Ford F-150s.

The NHTSA is probing claims that some of the trucks suddenly dropped into first gear—to the surprise of the drivers—regardless of how fast they were travelling.

The National Highway Traffic Safety Administration is investigating nearly 1.3 million Ford F-150 pickup trucks in the United States over reports of an unexpected gear downshift accompanied by a temporary rear wheel lock-up.