Federal regulators have opened an investigation into nearly 1.3 million Ford F-150 trucks after consumers complained the vehicle unexpectedly downshifted while traveling at high speeds, causing it to rapidly slow down and increasing the risk of a crash.

Ford used the 6R80 transmission in nearly all F-150 models from 2015 to 2017. However, the 2017 F-150 Raptor featured a 10-speed automatic, which was then used in most models star