My dashboard rattles a little bit, at the windshield..... I don't know yet how the dash is mounted, so I put a length of rubber vacuum hose between the windshield bottom and leading edge of the dash.
It works, I don't like band aids..... but it works.
There are clips under the dash that allow you to screw it into the metal brackets. They are known to break, that's my guess. Really cheap to fix, but a PITA to take all the dash off to do it.