19 Exp Max- hear grinding once in a while.

[Shannonsford]

As I'm driving my 2019 around 50-60 mph I will hear a slight grinding and feel it in the gas pedal too. I also had all the recalls done last week. Dealer can't find anything wrong cause ofcourse it doesn't happen when they take it for a test drive. Help please. We're leaving in 6 days for a 16 day driving trip and want to take the expedition.