What would cause a ticking noise in front of my envoy?

What is your question?

I'VE been told it could be a exhaust leak there is no issues so far with the way it's drives runs good and drives Well just changed oil and oil filter as Well as transmission and fuel filters.. it only has 134000 miles on it.. also I was driving tonight and I started hearing a metal clicking noise on front passenger side kind of like some thing was loose hitting something else I didn't see anything loose any ideas what could cause that?