My TT coupe has, since I got it, been stricken with an annoying squeak in the hatch. Whenever I hit bumps, I'd hear a high pitched squeak from the rear of my car. When I had a subwoofer, it got intolerable; every bass hit would be accompanied with a sound resembling a mouse stuck in my sub box.
This drove me crazy until I figured out what it was. At first, I suspected the rear deck lid (the removable mesh hatch cover) was the culprit. I was wrong. It was the interior panel on the hatch itself.
The panel is held in by clips...the same sort of design that holds on the fuse panel door and most of the interior panels on the TT and other cars. The two clips at the top of my hatch were loose and were therefore rubbing against their mounting holes causing a metallic squeak along with some rattling. This is how to go about fixing it...it's VERY simple.
First get some packing foam, I used a strip like this:
If you examine this area, you will likely find the grey panel to be somewhat loose:
Grab it and pull on it until it pops out somewhat, like this:
Now we can see the culprit! The clip is visible on the left:
Pull the hatch panel until you have the entire clip out; it will take some effort. While holding the panel out, cover the clip with your foam and push the panel back into place. Repeat for the other side. Trim any excess foam off with scissors for a clean looking fix.
You're done! Now hit as many bumps or make as much bass as you want with no squeaky hatch noises to accompany it.