2001 Chrysler T&C, all wheel drive: for months I was hearing a feeling a slight thudding sound from under the front of the car, maybe below the steering column every time the car went over slightly uneven pavement (only noticed it when the car was going slowly). One day, just after making a 90 degree turn, I heard and felt a giant thud, like I hit a small boulder (but I didn’t hit anything). Since then all thudding has stopped…should I be worried or relieved?
You should be worried, without seeing the vehicle one can only guess.
You need to pull it into a good front end shop and have them fully inspect everything. Whatever it is could be nothing (the neighbor’s kid’s tricycle finally fell out after getting stuck in there) - or something dangerous like a broken sway bar link, damaged ball joint that is shifting around…as waterboy said, without seeing…
Here’s another vote for an immediate front-end inspection. These vehicles eat their original antisway bar bushings pretty quickly, and start to clunk. But the rest of your story is cause for action asap.