UPDATE/dreaded rear clunking noise driving us crazy/UPDATE
 

My wife has a 2010 Town and Country Touring with 133,000 miles. I drove it a few weeks ago and thought to myself how quiet it was and how solid it felt. Later that day a loud clanking noise from the rear. The rear panhard bar (trailing arm as parts stores call it) broke in half. I put a new one on and it was quiet again for about half a day.
Dull thudding noise when going over bumps, even slowly. Replaced the rear shocks as one was shot. Still had the noise in the back. I recently replaced all 4 wheel hubs.
When I hit a bump you hear "thud thud" as if something is bouncing off something or bouncing between two surfaces.
Here is what else I've done to no avail:
1) shimmed between rear bumper cover and structure with rubber hose to firm that up
2) replaced 2 push-type fasteners on bottom of bumper cover with screws to make that secure
3) Used the tape method on the sliding door latches
4) Placed strips of rubber hose between the gas tank and the straps
--I did pound on the bottom of the gas tank and something is loose inside that makes a similar noise. I don't think it's my issue because just slowly going over a bump creates the noise
5) Tried putting the rear seats in all positions and test drive
6) put a pressure rod between the inner plastic panels behind the back seats to firm those up from rattling
7) Shock mounts and panhard bar are tight
8) adjusted rear liftgate to close as tight as possible
9) checked all lines and cables under van
10) spare tire is tight
With the kids sitting in the second row seats they say they can feel the thudding on the floor between the seats. Not sure if it can be felt in other places. My wife says she feels it by her feet in front passenger seat. It's clearly audible at the rear

At that age and mileage, IF it has a rear sway bar probably the end links and bushings are worn out. Also if still on the original front struts, those and the front sway bar end links are way overdue for replacement. I have an 04 T&C and i'm sure slightly different than your '10 model.

I took the bottom bolt out of the new rear shocks I just put on a month ago. I let the shocks hang down away from the control arms so they wouldn't contact anything. Drove it around the block and it was silent. Took those shocks back under warranty and upgraded from those Gas-Matics to Monroe Spectrums which are what used to be the Sensa-Tracs. Drove it around and it was silent. . The Gas-Matics were in solidly with no loose bushings and no loose bolts. They operated fine on the work bench just like when I took them out of the box. Both types had the same rubber bushings and sleeves