Actually, I'm having the same issue. I already put lubricant on the hinges and latches (I did this to all the doors) and put electrical tape over the metal hoop. However, I was just messing with the glass today. I noticed that I can wiggle the hydraulic supports near where they're attached to the glass and they seem to make the sound that I hear from back there (or at least that's the only thing I could get to make a similar sound). I might try tightening those down, but I don't want to crack the glass.