My wife's 2013 7 passenger SF 3.3 AWD started making a faint tapping sound from somewhere in the drivetrain yesterday. I made an appt with the dealership today and drove it about 12 miles there. I heard the sound the whole way, especially while under load. They diagnosed it as the AWD coupler with a $630 labor and $929.12 parts estimate for a grand total of $1,559.12. I'm worried that it's actually the entire rear diff though, and not just the coupling. From what I've gathered, if the coupler fails, you lose AWD and maybe hear some sort of constant bearing noise or whirring noise. Please listen to the noise in the video and see if it's anything you've heard before. I've searched all the threads on here and it doesn't seem like the issue I'm experiencing is a common one. Thanks all! (I cross posted this in the short wheelbase forum as well).