while driving on the freeway my 2014 ford f150 suddenly downshifted from 6th gear to 1st gear causing my rear wheels to lock up and having the steering wheel jerk to the left. the car behind me had to swerve to avoid hitting me from behind since the trucks wheels locked up with no brake lights. this has been the 8th time this has happened. each time i take it to ford for them to check it out they tell me they can not duplicate the issue. the wrench light comes on and it throws codes and ford will do nothing to fix it.