How do you know the Durango weighs 5330 lbs? Have you weighed it? If no, then I suggest that you do so first so you know exactly what you're up against.
As for being a couple of hundred pounds over, I would never recommend that you go ahead and pull it; however, I seriously doubt if it will cause a catastrophic failure in you hitch system the first few times. But over time, it will definitely cause undo ware and tare on the hitch and it's mounting point.
Another factor to take into count would be the extra strain on the engine and drive train of the mh.
It's your call, of course.
ron