My 2017 S (delivery in March) has been in service 3x for this, and this last time for over a week and they still can't figure out what's wrong or make the sound go away. Basically when going very slow, either in parking lots, alley ways or even in bumper-to-bumper on the freeway on autopilot, I feel a low rumbling sound like the car is going over rumble strips. It's faint, but it's there and more consistently so now. It usually starts when decelerating (not quite regenerating/braking yet, but hovering over that neutral line) and not in response to road conditions. Though if I go over something bumpy, the sound will occur AFTER the bumps not while I'm going over the bumps. They've taken the steering column apart, they've replaced the struts, they've replaced the shocks, and it still makes the sound. Anybody experience something similar or have an idea of what it is? I have to note I've driven several loaners during this time and NONE of them make a similar sound, though I have a coil suspension and loaners have air suspension and they think that may be why.