I think my 06 Pacifica is collecting water in the vent/heat ducts after a rain storm. I hear the water sloshing when I am backing up. The floors aren't wet, but I would like to address this before they are. My driveway has a very slight incline. I don't hear this when I have backed the car in and when driving forward.
Thanks in advance for responses..Joe

 

see the dealer and explain in detail