Squeaking or rattling? Those sound like two different issues.
Many people have had to adjust the striker plates and bolts on their rigs, if it's ratting. Also make sure you flip the dead bolt when moving. This sometimes helps secure the door (and keep it from popping open during transit

).
My door was squeaking when going down the road, so I sprayed all around the door seal and door frame with silicone spray, and that stopped the squeaking.