Help diagnose a noise please.... Rattle/ratcheting sound when coasting

For some time, my 2010 Sequoia has been making a sound I just can't diagnose. It only happens when the car is moving (not parked), hard to get a recording over road noise with my phone and the window open, dealer says they can't duplicate (but trust me... I am NOT crazy).

After I accelerate and take my foot off the gas, there is a quick ratcheting/rattling sound that will last a few seconds. It is a "mechanical sound". Sometimes when I start to brake it will do it again but not every time I brake. I don't feel any vibrations on the steering wheel, brake, or gas petal. I was thinking maybe something with the ABS system or maybe with the transmission/drivetrain when it isn't under acceleration pressures. Brakes work great, firm petal. Again, it NEVER makes the sound while accelerating. Any ideas?

 

check driveline brackets and anywhere there may be a torque induced flexing, I'm thinking the exhaust may have a loose or broken bracket.

 

That is a good idea.... I will check.