Hello and welcome to just answer. I had a 2010 Town and Country in my shop just the other day with the same complaint. Does the rattle sound as if it is in the B pillar area (the area between the sliding door and the driver's door), or does the sound seem to be coming from under the floor near the second row seats?
Ok, the problem may actually be in the striker/latch in the front driver's door. The van I had in the shop the other day was in that area, but sounded like it was in the sliding door. Open the driver's door, and using a #45 Torx wrench, loosen up the 2 striker bolts just enough so that the striker can be moved closer to the body (about 1/8"). Tighten the bolts and see if the noise is gone. This will make the door fit tighter and not rattle.