Sorry, but WD-40, PAM, etc aren't sufficient! White lithium grease or better yet BG HCF will work great-IF THAT"S WHAT IS WRONG! Carefully look at the hinges (especially the upper one) where the hinge plate is welded onto the body. Look at both while opening and closing the door a little and even try wiggling the door up and down by having a friend grab the rear lower corner of the door. If you see movement between the hinge and body it's welding time! This was common and an easy fix if you catch it before it breaks away.