Unexplainable, Undiagnoseable, Unlocateable Flapping/Gringing Sound

Couple of go pros mounted underneath the vehicle could maybe see what part of the vehicle the noises coming from the loudest

 

My Lexus RX 350 AWD will make the same noise at a local cafe. When I roll the front tires past drive up window they loose traction ( I assume slippery from mildew or pollen). And the back tires are on dry concrete, it’s make the same noise and vibration in brake pedal, but the TC light flashes 1-2 times.

 

Its ABS kicking in genius. Happens when you hit a bump hard. Of course they aint gonna find it in one test drive. You would have to hit a bump hard or fly through something and brake hard.