I have a 2013 GS 350 AWD F-sport. Approximately 3 weeks ago, I started noticing that my trunk seemed to be making loud sounds whenever I drove over a speed bump or made a sharp turn in either direction. It sounds like the trunk itself is loose. Can the trunk just become loose by itself like that? When I try to jiggle the trunk, it seems solid, though. Does anyone have any suggestions as to what it might be and what I can do? Thanks.

Check under the floor mat/trunk floor to see if the spare tire or any of the tools are loose. I doubt it's the trunk lid.

Thanks. I checked the spare. The nut that holds it in was a little loose, but enough to cause the sounds. I did tighten it, though. There are still sounds emanating from the trunk when I turn or go over a speed bump. Would you happen to have any other suggestions? Thanks.

Take out the trunk liner and find out whats loose or moving around under there.

Chances are - whatever is making the noise is not actually in the trunk. It just sounds like it's coming from the trunk. Noise can easily sound like it's coming from one area when it is really coming from somewhere totally different.

I would check these areas in particular:
Sunroof (noise can be transmitted through the rear pillars)
Struts (Rear & Front) including mount hardware and cups
Sway Bar bushings including link nuts

My guess it's the sunroof.

If I'm correctly assuming that the trunk is at the rear of the vehicle, could it be a busted exhaust hanger? There isn't much else to move underneath, maybe give both a wiggle, it'll take 15 seconds.
Bclexus' list​​​ looks like a great place to start. A suspension shop should be able to give it a once over to rule out some suggestions

You're right about the struts! The left rear was leaking like crazy, and the left front was leaking a little. I'm having them replaced. My vehicle only has 45K miles on it. Does that seem early to need to replace struts?

More information is needed...

Are you the original owner? If not, do you know how the car was treated before you purchased it? Have you lowered the car? Lowering springs will really stress struts/shocks. Has the car been driven on poorly paved roads? Driven aggressively or tracked?

If your not the first owner the car may have been previously lowered and had larger rims, putting a lot more stress on the stock struts leading to the premature failure. Or they hit a lot of potholes and speed bumps at full speed.

Good questions. I'm not the original owner, but from the look of the car and the maintenance history, it seems that the car was well taken care of. I haven't lowered the car. I don't track the car or drive aggressively. I have gone over a few potholes, though. I can't seem to avoid all of the many that are on the road where I live.

Struts are a lot like light bulbs. If the average life of a light bulb is say 1,000 hours, some of the light bulbs will last much longer and some will burn out much sooner...with some burning out right away. And again, much like light bulbs - if you turn the light bulbs On and Off often they will burn out in fewer hours than if they are left On for many hours at a time.

Also most 100k miles on my GS and no leaking struts.

I'm envious 😁 Those struts set me back a pretty penny.

Thanks for the checklist! I too thought my clunking was coming from the trunk, but couldn't find anything loose. After seeing this thread, I found it is the sunroof making the noise. Sound like I need to have the rubber seal lubricated or replaced.