I have a 2011 Chrysler 300c

Hello, I appreciate that this is an annoying noise and hard to pin point on your own! Unfortunately, from here, it's even harder to try and help you figure out. You'll be best taking your Chrysler to a local technician near you who is skilled and experienced at looking into and resolving these kinds of concerns. Good luck!

My parents had the same noise, coming from body mounts in rear of car all it takes is to have it up on a lift and tighten all body mounts in rear of car.