[moto22]

I had the clack behind the radio - and lo and behold after months of thinking that was where the sound was coming from I found it was the rear view mirror mounting arm. The plastic just prior to the headliner was where the creak was coming from. It did sound like it was behind the radio though until I got my girlfriend to drive while I listened and zeroed it to the mirror mount arm. I pressed on it a little and no more clack.

Try it - it may help in your case too.