Cherokee Groan
 

Hi, new to the forums here.
I have a 2016 Cherokee Trailhawk and I have an odd sound I've never heard before in other vehicles of mine. While braking you can hear a groan, like the Jeep is aching from something. It groans loud enough that sometimes the springs vibrate. It relate makes noise when braking over bumps. Driving over bumps without braking doesn't seems to make noise, at least not that i can hear.

It's already gone back to the dealer twice for brakes and rotors and it seems to get better but eventually comes back.

Any ideas?