Slow speed klunk starting and stopping

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 279

I have noticed a klunk whenever I start off from a stop, and a similar klunk when I am slowing down to stop. Both happen at fairly low speed. And they are usually there, at least I hear them whenever I remember to listen for them. Not really sure if it is front or back. And they have been around a while (months) and so far aren't getting worse. Does not seem to be related to the applying of power more just the speed one is going.

The weather here is supposed to warm up and dry out some in the next week, so I thought it might be a good time to crawl under and see if I can pinpoint the source(s) of these klunks. I was thinking might be ball joints, engine/tranny mounts. Any ideas as to what I should be checking (and how)?

In a related vein, it is also time for some new shocks/struts (94K miles). From my measurements when I got the CRD seems it has sagged about 1/2" in front. I am wondering what folks would recommend in way of shocks and if new springs are going to be needed too. I really don't have need for any extra lift, and did not know if just putting new struts in would bring it back to original height. If not, is there a new spring kit that would add an inch or so?

As far as shocks go, I travel over several miles of dirt roads each day, all with washboards. So I am not keen on a really stiff shock. Have had bad luck with Bilsteins (end broke off at a weld and the co refused to honor their warantee), although I hear many folks here like them. What else is good and perhaps comparable to the stock shocks?

Thanks

jws84_02 · **Posted:** Sun Jan 29, 2017 9:45 am

Check and make sure both motor mounts are tight

rankom · **Posted:** Sun Jan 29, 2017 10:02 am

check parking brake -shoes and mounting plate , broken rivets ?

Hexus · **Posted:** Sun Jan 29, 2017 10:21 am

Most likely front axle CV joints. Lay underneath and grab the front axle with your hand and twist it. If it slams back and forth (clunks), then you've found the problem.

WWDiesel · **Posted:** Sun Jan 29, 2017 11:08 am

Could possibly be the rubber bushings on the rear upper control arm (boomerang) are busted and maybe loose. They mount right under the back seat on both sides and can make a klunking noise when the arm pivots fore and aft due to rotational torque of the rear axle... :?:

taroo · **Joined:** Sun Apr 27, 2008 2:14 pm **Posts:** 276

WWDiesel wrote:

Could possibly be the rubber bushings on the rear upper control arm (boomerang) are busted and maybe loose. They mount right under the back seat on both sides and can make a klunking noise when the arm pivots fore and aft due to rotational torque of the rear axle... :?:

I had the same issue and found it to be weak bushings on the lower rear control arms. I changed the upper control arm a part of trying to narrow down the source of the clunk. by the way, the upper was busted so needed to be changed anyway. But changing the lowers dealt with the issue. Do check the rear u-joint of course.

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 279

Well, it's been a few months but I am back to playing detective trying to find the source of this clunk. Again the clunks only seem to happen at slow speed, like when coming to a stop just before or as you're stopped, and again when starting up just as you start moving. Usually only when stopping from relatively high speeds (>45mph), and after it has warmed up some; does not seem to happen when you just start off and are going slow say around the block. FWIW the sound seems to be from the passenger side rear, but judging location from inside the cab is an iffy thing. Does not seem to effect steering or handling any, just an annoying low speed clunk at stops and starts.

What I have checked is:

Rear lower control arms (can't move the bushings with an 18" pry bar).

U-joints on the drive shafts, none seem to be loose or failing.

Engine mounts, pass side looks a bit worn but neither is collapsed. Can't really say much diff in idle noise between drive and reverse (GDE's test) but may not be a bad idea to replace the pass side one at least.

Looked at the rear upper control arm, but not entirely sure how to test it. No obvious play at any of the bushings with a pry bar, but it was on the ground so not that much room for leverage.

Only other thing I can think of is the rear brakes. I assume just looking for play in the caliper on the slider pins there. How about that upper control arm, how does one test for a failed bushing there?

Thoughts, ideas?

wilco549 · **Posted:** Tue Jul 25, 2017 7:57 am

Not trying to hijack your thread but I'm having a similar problem: low speed clunk but mine is mostly when the body shifts, say turning in or going over a speed bump. I can make it do it at time during abrupt accel and decel. I've changed rear lower arm 2 yrs ago, upper wishbone 3 months ago and am getting ready to install prebuilt Monroe "struts" on the front and new shocks on rear. I have 150k on mine.

i also plan on check all trans mount bolts, motor mounts again(I checked them 6 months ago) and all ball joints, bushings, etc.

Funny thing is that sometimes it's quite, and sometime clunky. Seems to be worse with passenger....but it may just be my stereo volume is lower.

APC9199 · **Posted:** Tue Jul 25, 2017 9:29 am

This is kind of a hokey way to check things, but it has worked for me a few times in the past. It is easier if you have side steps and a hitch.

Try hanging off of one side of the Jeep and bouncing up and down to see if you can make the noise happen. If not, try the other side. If that doesn't work, try to rear end, and the front after that. If you are able to make the noise happen when moving the body, then have someone else do the bouncing while you crawl underneath (with wheels chocked, etc) to find where the noise is coming from.

It is cheap and easy to do and might be the quickest way to track down one of your problems.

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 279

Thanks APC9199. Done that on other cars/problems. On this one tho the problem only seems to happen with shifts of something heavy, like coming to a stop or starting up, and sometimes when going thru a curve quickly. Sounds/feels like something massive moving in the horizontal plane just a bit to make the clunk. I don't think bouncing will cause it to happen.

Perhaps I just should change that pass side engine mount, it seems to be the most likely source (if the rear brakes don't show anything loose). Soon as the rains stop I'll get back on this.

mrhemi · **Joined:** Tue Dec 08, 2015 10:46 am **Posts:** 180

I had this or a similar noise and conditions on my 2006. Turned out to be the front lower control arm bolts were lose, where the caster and camber is adjusted, allowing them to slide in the slot. As it got worse, you could feel a shift in the steering. That is what lead me to look at those. Sure enough, barely tight. Immediately torqued them to spec and got it to an alignment shop for a re-alignment. Clunk went away.

flash7210 · **Posted:** Thu Jul 27, 2017 11:12 am

I get a light clunk when coming to a slow stop and slowly starting forward again.
Seems to be coming from the transmission tailshaft area.
Trans mount looks good. U joints seem good.
I think it might be the drive shaft slip joint.

GordnadoCRD · **Posted:** Thu Jul 27, 2017 8:24 pm

That sounds like mine too.
It feels like the 2-1 downshift happens as my foot is coming off the brakes.
Not necessarily all the way off, but as the brakes are being released, and finishing the shift as my foot hits the accelerator.
I put in an extra quart, but that didn't make any difference.
U-joints are tight. No play in the slip joint that I can discern, and no excessive differential play.

flash7210 · **Posted:** Thu Jul 27, 2017 9:00 pm

GordnadoCRD wrote:

That sounds like mine too.
It feels like the 2-1 downshift happens as my foot is coming off the brakes.
Not necessarily all the way off, but as the brakes are being released, and finishing the shift as my foot hits the accelerator.
I put in an extra quart, but that didn't make any difference.
U-joints are tight. No play in the slip joint that I can discern, and no excessive differential play.

According to the 545rfe service manual, the L/R clutch is only applied when output shaft speed is below 150rpm.
Maybe thats what we are feeling. The apply or release of that clutch.

GordnadoCRD · **Posted:** Thu Jul 27, 2017 9:55 pm

That comes out to about 2 mph with stock gears and tires, so that could very well be.

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 279

Interesting possibility the clutch. But would the release/engaging of that clutch cause a clunk? I would think it was a simple solenoid and not that loud.

GordnadoCRD · **Posted:** Thu Jul 27, 2017 10:16 pm

As we're not able to feel what you feel and hear what you hear, the only thing we have to relate to, is the timing of the event.

In my case, there is an audible clunk, but it varies, depending on how much pedal I've applied.

The specific condition of your chassis would also cause variations that we can only guess at.

AS such, I would say yes it's possible, but without hearing/feeling your 'event' we really can't know for sure.

There does seem to be a mechanical event with similar timing, that may be aggravated by some mechanical condition unique to your vehicle, to make a different feel or a louder sound.

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 279

You're right, without hearing and feeling each of these clunks, it's not possible to say if they are the same or not.

On mine, it does sound and feel very much like a heavy piece of metal moving/shifting and hitting a stop when the clunk happens. Like if a suspension bushing or engine mount were worn/loose and some big pieces are shifting until they come to a stop. Of course could be something else too. But on others could easily be the noise from a solenoid.

FWIW, I was at the Jeep dealer a few days ago getting some keys programmed. They took a quick look at things and I asked them to see if they could find the source of the clunk. They checked all the simple things (after all this was a free inspection for customer safety and to find some low hanging fruit for them) and said they could dup the clunk but could not find a source. It did not seem to be the brakes, tho.

I am still thinking that the engine mount is a likely candidate for the source. Probably would not hurt to just replace it, but is there any test which does not require removing the mount which can check them?

GordnadoCRD · **Posted:** Mon Jul 31, 2017 7:50 pm

Engine mounts are a bit of a weak point for the CRDs. The RH one seems to fail faster than the LH.

Perhaps you could duct-tape a camera (phone?) under the vehicle where it can "see" suspect parts while you drive the vehicle and make it do it's thing?
Or if you have a mag-mounted gopro...

Steve777 · **Joined:** Fri Oct 16, 2015 11:31 pm **Posts:** 279

Thanks Gordnado, I do have an old junk iPhone that has enough battery left to record for a min or so. I'll try to rig that up...

One other thing, I seem to recall there was TSB/Service Bulletin for replacing the rear upper control arm on Liberties. I sort of remember reading about it but could not find it when I searched for it recently. Does anyone have a link or number to such a recall? I fit does exist I might get Chrysler to replace this and it may be related to my clunks...

Slow speed klunk starting and stopping

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