I've done some searches on this, and all I can find is the very common clunking sound coming from the rear suspension (which I've heard before on a test drive of another FD a few years ago)

My car is starting to make a creaking noise from the rear when going over bumps. Could this be the springs or shocks? Or a variation on the clunking sound and I just need to replace the bushings?

 

It could be what you mentioned, but I would look towards springs first. Mine starting creaking when they got a little older.
You would do well to jack the car up, and start pulling on things to see what's loose though.

 

Well, I have a set of Eibach springs that are going on this weekend, so hopefully that will fix the problem, but I'll take a good look and pictures of all the bushings when we do it to see if there are any problems.

 

It's probably your interior

 

Mine does the same thing, I found it coming from the where the springs meet up with the shocks. The rubber spacer thing is wearing out.

 

The top strut mounts on our cars seem to do that...I just replaced mine in the front to solve some rubbing issues. I can see how that would happen in the rear as well.

Whenever I do suspension or brake work, I like to spray some wd-40 or silicone lubricant on all the joints, spacers, etc. No squeaky problems for me...

 

I had a really bad creaking from the rear once upon a time ago...after looking for it forever and spraying the whole rear end down with a lubricant 10 times, finally found it, turned out to be a pillow ball bushing. I simply took the rubber protector off and re-greased it. Unfortunitly, they started clunking soon thereafter and ended up replacing them.

 

The rear hatch is known to creak when the rubber stoppers at the rear corners get hard. Try smearing a little grease on them and see if it shuts up. After that I would check the upper spring seats (strut mounts) as others have mentioned.

 

Thanks for all the suggestions guys, I'll check all these things out

 

Exactly what I was thinking.

Here is a link with some more info on how to fix this:

 

The car has a very low load rating... between 3 and 4 hundred pounds I think.

So, if you had someone else in the car when you heard it and you are not both average sized, the sound might just be the suspension creaking under the weight.

I am over 200 and so is a friend I sometimes ride with. I only hear the creaking with another in the car.

 

My rear hatch is creaking, I had a passenger reach back and apply upward pressure on it and it went away, give that a shot.

 

Come to think of it, I only seem to hear it when my wife is in the car with me, together we're about 310 lbs.

 

It is also possible for the rear swaybar mounts to squeak as well. Although it's a lot less common as they are made from rubber and not urethane.

 

One of the ends of my rear sway bars was not even connected! That sure fixed a minor problem on my car. give us feed back on what you did (change springs, grease on rubber) and if anything worked.

 

No offense, but I think it might be easier to get someone heavy into the car and drive around a little.