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.

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.

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