I have a 10 ford flex ecoboost I've owned it over five years now and it feels like it randomly drops into neutral and if I keep a foot on the pedal when Accelerating it makes a loud slamming noise. No check engine lights ever come on during, before or after. Took it to dealer today , they test drove it with computer connected and did not get any codes. Now what can I do? Any help will be really appreciated. Thanks