I have had all three late model brand trucks and all have had some sort of rattle or squeak! My latest 2011 FX4 also has a rattle in the passenger door or rear suicide door. I also have a clank in the drivetrain which is supposedly normal driveline lash!

When I get real tired of that rattle I plan on taking the door panel off and finding the culprait.
Other then that it is an awesome truck.