I have a 05 grand caravan with 50,000 mils on a 3.3ltr.

it makes this deep thumping noise and you can feel it in the front floorboard on both sides, when going 15 mph or turning the wheel back and forth real fast while drivng slow. I checked everthing under there to make sure its tight, even changed one strut. sway bar bushings look fine even took em out to see.

any ideas? could it be the subframe mounts rubbing?

 

I would say change the sway bar bushings even though they look fine. They go bad fast. If the noise is still there, try the stabilizer links. I did both, noise went away.