200 Camry - tincan noise

I have a 2000 Camry with 60K miles. Recently I have noticed that it makes a sound (5 seconds) when I take a left turn as if someone is banging a wood stick in a tin can. The sound seems to come from read right. I had it checked out but the mechanic could not hear the sound. It is very soft. Very rarely it also comes when driving straight or reverse. It is automatic transmission.

does it have cv joints? there are other possiblities, such as a loose exhaust hanger, or a loose heat sheild. A worn out bushing can also cause this kind of sound, or something loose in the brakes such as a broken brake returne spring if it has rear drums.
take the mechanic for a ride, duplicate the noise, and buy him a cappuchino.

I do not know if it has CV joints. I had the mechanic check the exhaust, suspension, etc. and he said that there was nothing wrong with the car.

Yes, it definitely has CV joints, just like every other FWD vehicle.
Have the CV joints checked.

one other thing it could be, if the baffels in the mufler are loose, that will do it too. and it is not something the mechanic can see, or hear until it happens.

It could either be brake-related (which he did not check) or baffels in the muffler. How much that would cost?
How serious it is?
Interestingly, for a few days the sound had gone away and then it came back again in the last week.