We own a 2009 Monaco Cayman. The rear grill that covers the radiator recently fell off while driving down the highway. The doors on each side of the grill continue to come open while driving. These doors act as a second defense to hold the grill on the coach. We just had the grill replaced and upon driving home from the shop both doors came open again and the grill was loose. Has anyone else experienced this and do you have any ideas for a fix?