[ossiblue]

Look at the metal bar/shaft running from the interior door handle to the latch. It should be supported along its route by some type of "insulators" that keep it away from the interior metal frame. I can't remember exactly where or how many, or if they are plastic or foam, but I do remember seeing them as the bar passes closely to the framing.

Another place to look is at at the locking shaft, running from the button near the front of the door top to the rear where the lock/latch is located. It too should have some isolation from hitting against the door frame.

Finally, the door window mechanism should also be secure with the lifting arms not being able to vibrate against each other.