[Zoomad75]

Bingo. Hinge bushings are your problem. Be carefull with the slamming of the door until then. Mine were so bad all that slamming actually caused the door jamb to crack around the striker pin on one side. The other side the pin was getting hit so hard it actually bent the jamb at the stiker pin so the pin wasn't perpendicular to the jamb anymore.

I'd take close look at the hinge bushings while somebody lifted up on the rear of the door and look at the jamb for signs of cracking. If you see either I'd fix it sooner than later. Cold or otherwise I'd find a place to do it.

Mine were so bad you had to practiaclly kick the door to shut it tight though. Your's may not be as bad so you might be able to wait a little while.