Metallic Chatter

my 97 subaru outback is making a metallic chatter when I am driving. The noise only occurs while the vehicle is moving; reverse and forward. With the vehicle in park or nuetral the noise cannot be duplicated. It comes pretty intermittently and today much worse than ever before. Any thoughts on what it may be?

Can you tell where the noise is coming from? And are there any conditions under which the noise always happens?

Do you hear the noise when you apply the brakes, or only when the brakes are not applied?

The noise is comming from underneath the car, I can’t tell from whic side I hear it more of if it ic comming from the front or rear. Th enoise happens sporadically, but always when th evehicle is moving, even when the brakes are applied and decelerating. The can continue until I am at a complete stop and this morning, with colder temps, the noise was not nearly as loud or frequent.