Clunk in the trunk

[Ken_W]

When going over bumps it sounds like an empty Igloo cooler is loose in my trunk, the noise only lasts for fraction of a second after the bump, but something is definitely loose.

I've tried:

- Taken EVERYTHING out of the trunk, including spare tire and related accessories

- Replaced rear shocks and upper mounts

- Replaced lower rear control arm bushings with new

- Replaced rear suspension lateral links with new

- Inspected (while replacing above) all three rear subframe mounts, no obvious problems found

- Inspected (while replacing above) all rubber exhaust mounts, no obvious problems found


It seems like the noise is coming more from the passenger side. I had my son ride in the back seat and listen through the armrest hole, and he also thought it was coming from the passenger side (but could not pinpoint it).

Any ideas of what to try next?

Ken_W

[00Beast]

I have a similar noise. I think mine's coming somewhere from the rear deck...

[yonkerse]

I had this same type of noise coming from mine. Had the dealer check it out and they replaced the rear shocks and mounts (under warranty) and this took care of my clunk/rattle noise....

Seeing you already replaced those..not so sure..

[harofreak00]

Ride in the trunk... I did.

[Tdpontiac]

Have same noise. Did you ever determine the problem?

[Ken_W]

I think I have narrowed it down to bad subframe bushings underneath the car. These are the thick rubber mounts that hold the rear suspension to the underbody. Mine are visibly dry rotted on the outside, and two mechanics independently told me that they have too much play. This would explain the clunk -- the suspension is bouncing around as I drive, causing the clunking noises. I think the rear-most ones are the most to blame.

It should be noted that my rear end is obviously unstable when I drive at higher speeds. The back end even seems to jump sideways when I go over bumps. This is another problem that the new mounts should solve.

Am hoping to get these bushings/mounts (different people call them different things; GM calls them "Insulators") replaced sometime this month. I'll report back here as to whether this solved it or not.

Ken_W

[riktik]

I have the same thing after replacing the rear shocks and mounts. Also, only on the passenger side. I flipped the cupped washer around (upside down) for a day and didnt seem to help too much but when I flipped it back over I found that for a little while the noise was gone (fingers got drawn in, made better contact with the cupped washer when I flipped it back around). What I seem to be getting is the cupped washer clamping down on the inner member of the mount rather than resting on the elastomer fingers on the outer member. I am going to cut down the inner member using a mill and see if that makes any difference. The problem with it clamping onto the inner member is that it is not isolating the stud on the shock, and with the inner member of the mount having as much clearance as it does around said stud it can wobble in there and create this noise. I will post back when I find out if it changes anything. I'll be looking forward to hear if the subframe isolators make any difference as well.

[Mark Fahey]

This must be catching. I replaced my shocks and mounts last week and now I have a definite clunk at certain times going over bumps. I've checked and rechecked everything for correct torques. With all new everything, this just doesn't make sense.

[Ken_W]

I replaced my shocks with Monroe Max-Air's last summer and I do have some kind of noise coming from one of those. Since my original clunking problem drowns it out, I've put it on the back burner for now (but I am interested in what other people are finding).

Ken_W

[2003BlackSapphireSLE]

its the shocks. i replaced mine with monroe max airs as well. and all of a sudden i got a clunk. replaced mounts, same noise. I lived with it for about 3 years now. i replaced my dads shocks with the same kind on his 05 and all of a sudden hes got the clunks too. I guess thats what you get for aftermarket crap.

[2002FO]

Sorry to resurrect an old thread, but has anyone come up with a definitive explanation for this clunking sound? Mine, too has the elusive clunk....

[00Beast]

Loose shocks. Tightened my shocks this summer, went away, now it's back. Even 1/4 or 1/2 turn can do it.

[Ken_W]

I went in and tightened the shock further whilst holding the center shaft steady with a wrench. Probably got it a quarter turn tighter, and that helped enough for me to be able to live with it.

[2002FO]

Yeah, they're tight, but still, sounds like an empty cooler bouncing around in the trunk.... I'm on vacation next week, so I may just replace them. They've been in there for probably 4 years...

[golfyeti]

I replaced the shocks and mounts twice. Nope, it was lose body mount bolts. A 30 cent thicker washer placed on them eliminated the clunk for good. I cringed about that clunk for two years. Search for body mount bolt or click on this link
viewtopic.php?f=18&t=13804&p=145308&hil ... ts#p145308

P.S. I'm no longer awol. bringing "Precious" back to life really soon!