Who has had clunks in the trunk after installing new shocks?

[Ken_W]

I am wrestling with this since installing new Monroe MaxAir's last fall. Upon searching old posts, I saw someone post the same complaint about AC Delco's as well.

Am wondering how common this is. Please post here if this has happened to you. If you figured out the problem and solved it, most definitely post and share what you did.

Otherwise, please let us know:

1) Does/did it clunk on one side or both? If one, which one? (Mine is passenger-side only)

2) Did you hold the center shaft while torquing the center nut, or let it twist a little? (I let it twist)

3) Can you see any spindle threads above the center nut? If so, how many? (I see zero on driver side and two on passenger)

4) Did you install a new shock mount? If so, what brand? (I put in new Moogs)


I have a feeling that there is a simple solution to this out there; maybe if we work together we can find it.

Ken_W

[theax40]

I bought my SLE from a GM dealership and they replaced both rear struts when I bought it, either Monroe or AC Delco most likely. Slowly over the last few months, I've been wondering why it's so loud back there when hitting a bad bump or train tracks. I just wrote it off as junk in my trunk (HAHA!!) but after cleaning the trunk out, it's still noisier than I think it should be. Passenger side only.

When I bought it, they let me take it home right away. The car needed pads, rotors, water pump and struts and they were booked solid for the week, so they scheduled a day to bring it back for all repairs. I drove it for about a week with bad, clunking struts. After they replaced them, the contrast from loud struts to new struts was so great that if the new ones clunked like they do today, I doubt I would have thought they were loud at the time. Much quieter than the old ones, at least.

So maybe the new ones have been clunking the whole time and it just took my ears 6 months to adjust to the new sound and finally notice how loud the one really is?

[94SilverSSEi]

I get some clunking/popping.

At first I thought it was steering rack, then I thought front strut mount and now I think it is rear strut mounts.....
I put new rear struts and mounts. I'm wondering if the mount were not torqued to the strut enough or possibly something else. They were tight but the crazy (star or hex?) stripped out and that was that.

It is kind of random and intermittent and doesn't seem to affect anything, so I just ignore it.


Those little noises add character

[crash93ssei]

I thought you had it narrowed down to the subframe bushings back there being fried?

[Ken_W]

@crash93SSEi - I've determined that I have two separate problems back there, so I thought I'd split this one out as a separate topic. The two mechanics who ID'd the bushings problem also noted the rear-RH shock issue, as did the alignment shop I last went to. (Unfortunately none of them offered up a solution) The subframe bushings job is a bigger job, so I'm going after the (hopefully) easier one first.

Ken_W

[Archon]

A bit after buying my car, the shock rod went right through the mount. I bought new shocks (don't recall the brand, but wasn't Monroe) and mounts. The car rode like a buckboard, and had a fair amount of noise. Replaced the shocks with Monroe's and Monroe mounts. It rode better, but the noise was still there. I tried several brands of mounts, and finally landed on the Moogs. They were quieter than the rest, and after about a month or so they quieted down.

My clunk was mostly limited to the driver's side. I did hold the shock rod steady while tightening the nut. I'd have to check on the threads.

[crash93ssei]

I replaced the shocks on the 03, new bushings top and bottom, never had any clunks or any odd noise at all.

[Ken_W]

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[Ken_W]

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[Ken_W]

Trying to troubleshoot this thing in a methodical way... I think I've listed every (reasonable) possibility here:

-------------------------------------------------
Bad Install
..... Center nut improperly torqued?
..... Grease not properly applied to hardware?
..... Part damaged during install
............ Mount damaged?
............ Shock damaged?
............ Hardware damaged?

Bad Parts
..... Defective Strut?
..... Defective Mount?

Incompatible parts
..... Used mount hardware, should have used strut hardware? (or vice versa)

--------------------------------------------------

Since I've seen other reports of this going back to 2005, my case can't be a fluke. There's got to be a common cause of some sort.

Here's an avenue to investigate: I recall that both my shocks and mounts came with hardware (nuts and the conical washers that go above/below the mount). I don't recall which set I used, but I wonder if one set works better than the other? I seem to recall that they were NOT identical; something was different between them. Maybe this could be the root cause -- maybe the set I didn't choose would have worked better? I'm pretty sure I threw out the leftovers, but will have to double-check.

I guess I'm sorta thinking out loud here; hoping that one of these thoughts will stir up a "Eureka!" moment in somebody...

My "gut instinct" thinks that it can be narrowed down to these possibilities:

- Center nut improperly torqued
- Shock damaged during install (from over-extension or from not holding center spindle)
- Defective shock
- Incompatible hardware

Thoughts?

Ken_W

[Mark Fahey]

I just installed new Delcos and am getting a clunk in the right side. I have been over and over it checking torques and any other thing I can think of with no luck so far. It doesn't do it all the time but still, it didn't do it before I installed the new shocks and mounts so it has to either be something I did wrong or one of the parts is defective.

[Grimm]

Replaced mine with the Monroes a year and a half ago, but reused the mounts I had as they looked fine. I get an occasional clunk in the back when I go over a certain set of railroad tracks on the way to work if I'm going like 45 or more. I haven't investigated it, but I don't think it's from the shock area. Otherwise no clunks. I can only see one or two threads.

Just thinking out loud here, not recalling exactly how the mount and top of the shock looked, but could the new mount be shorter and not enough threads on the shock to tighten the nut sufficiently allowing a slight bit of slop as the wheel hits a bump? I remember jacking up the control arm when I did them to make sure the shock was tight up to the mount to make sure I got the nut good and tight.

[vogie01]

Didn't another member have this same problem and narrow down to something else? I will have to search for the thread.

[Mark Fahey]

Replaced mine with the Monroes a year and a half ago, but reused the mounts I had as they looked fine. I get an occasional clunk in the back when I go over a certain set of railroad tracks on the way to work if I'm going like 45 or more. I haven't investigated it, but I don't think it's from the shock area. Otherwise no clunks. I can only see one or two threads.

Just thinking out loud here, not recalling exactly how the mount and top of the shock looked, but could the new mount be shorter and not enough threads on the shock to tighten the nut sufficiently allowing a slight bit of slop as the wheel hits a bump? I remember jacking up the control arm when I did them to make sure the shock was tight up to the mount to make sure I got the nut good and tight.

In my case, the rod on the Delcos was indeed shorter by 3/8" which make it impossible for one person to hold the rod while tightening the nut. I think that I have the nut torqued correctly but to be double sure, I bought a strap wrench which I'm going to have my wife use to hold the shock from rotating while I torque the nut.

[crash93ssei]

The shock itself is bolted to the lower control arm so holding it with a strap wrench won't do anything as the shock body already can't turn when bolted in. Also, the shock rod and valve assembly will spin inside the shock housing anyway so holding the body from spinning will do no good either way. It is the rod itself that must be kept from spinning to ensure the nut on top is tight.

[74b5roadrunner]

Local GM dealer did mine, and yes I have the clunk

[Mark Fahey]

Very strange. We took a 250 mile trip yesterday on a typically rough Illinois interstate. The clunk was still there for much of the first 1/2 of the trip but completely stopped after that. It's as if the mount had to wear in, get fully seated or who knows what.

[Ken_W]

@Mark Fahey -- is it still gone?

@everybody else -- I finally got around to trying something today. At Harofreak00's suggestion, I crawled inside the trunk and had my wife drive me around. I had the trunk pretty much stripped out of everything that didn't have to be there, to narrow down potential clunk sources besides the shocks.

With my face only a few inches from the suspect shock (and flashlight in hand) I was able to confirm that the top of the passenger-side shock had too much play and was indeed the source of the noise.

I then (after getting out of the trunk) tightened the center nut on that shock a half-turn (180-degrees) while holding the center spindle steady with a second wrench. I then got in and took it for a drive, going over known bumpy roads.

The problem appears to be solved. I can't say 100%, but at least 80-90%. That's enough for me to be able to live with it. I don't really want to torque that nut any more, but we'll see how it goes. With things like this I like to drive around for a week or so (especially on my normal weekday commute) before declaring victory. But for now -- preliminary result -- it seems to have improved greatly.

Ken_W

[Mark Fahey]

It's mostly gone but pops up every now and then. I'll check for tightness again but I may just have to live with it.

[nlconner]

I too had the notorious clunk/rattle at low speeds. This was really noticable when I pulled in to my gravel driveway. Well, I did all of the suggested stuff (new shocks,mounts,etc) none of thant stuff got rid of the rattling. I put some focus on the Lateral Links and balljoint on the end of them. Mine were completely shot! I replaced both lateral links with the mavotech option and ALL of my noise went away. Just a suggestion, since you are down there anyway, pop your balljoint out of the control arm and check for slop! These were easily replaced in under an hour and costed $58 for BOTH shipped from ebay. You will need an alignment if you do replace them.