Really bad during stop and go,slow speeds, etc. Never happens at speeds over 20. Sounds like it is underneath maybe near the rear or middle of the vehicle. Kind of sounds like a deep throated duck honking, or a loud rubbing sound. Hard to describe, but very audible and can sometimes feel the noise. Can go for a few weeks not hearing it and then it returns for a couple days. Seemed really bad this evening in traffic, plus cold temps maybe. Dunno.