I've had occasion over the last few weeks to park in a quiet underground garage. I've notice about 5 times now that when I am rolling along at very low speed in a straight line while looking for a parking spot, that there's a strange sound almost like gravel rolling around inside a tin can when I lift my foot from the accelerator pedal. I think that most of the time I'm in "L" mode, but I can't be sure that's always been the case. I've rolled down the windows to hear it better and the sound only happens when lifting off the gas, otherwise the car drives fine and has no issues. The noise is subtile enough that it might be happening more frequently and I just haven't heard it above normal traffic sounds, only in this quiet parking garage.
The noise has so far not been repeatable. I've tried to make it happen purposefully several times so that I could record it and it won't do it, then out of blue it will do it again, so a trip to the dealer will probably be futile.
If it happened while turning I would think maybe the front U joints, but it happens in a straight line.
Has anyone experienced such a sound or similar problem? The car has 35K flawless miles on it so far, with regular maintenance having been performed.