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NHMJXJ

Mysterious "clunk", please help.

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I posed this question in my own thread for "other cool stuff", but there's not as much traffic.  I know it's not an MJ, but there has to be some parallels.

 

Having some unhappiness here.  I've have a "clunking" that emanates from one, or perhaps two places. 

 

Now bare in mind, I drive my XJ like a car.  On a smooth surface under 60MPH it rides beautifully.  Nice, quiet, smooth.  However, when I pass over even the slightest crack in the road I get a clunk the seems to come from the left front. When I'm on the highway traveling over 65MPH the clunk becomes almost rotational and I can feel it at my feet.  The driveline is a little loud when the 4wd in engaged (traveling at speed 50MPH-ish), but it has no effect on the clunk.  

 

Nothing is visibly loose.  I slid under it with all four wheels on the ground and knocked and shook everything I could reach.  Nothing moved.  Any ideas? 

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7 hours ago, Jeep Driver said:

Tighten the four bolts on the TB mount at the frame. 

 

 

This^^

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Please forgive my ignorance ... TB? 

 

In my line of work that involves a cough and no bolts.

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Everything is tight up there.  Went over every nut and bolt and nothing moved.  I had a lift installed last year with adjustable control arms, so my first effort was to bring it back and have them take a look.  I was disappointed with the response "XJ's do that".   My own shop can't find it either, although the service manager said it might be the transfer case.

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Check the front drive shaft slip yoke for play. My MJ has a clunk in the front end and it is the shaft. You can replace the bushing and seal on the slip yoke to get rid of it.

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I posed this question in my own thread for "other cool stuff", but there's not as much traffic.  I know it's not an MJ, but there has to be some parallels.
 
Having some unhappiness here.  I've have a "clunking" that emanates from one, or perhaps two places. 
 
Now bare in mind, I drive my XJ like a car.  On a smooth surface under 60MPH it rides beautifully.  Nice, quiet, smooth.  However, when I pass over even the slightest crack in the road I get a clunk the seems to come from the left front. When I'm on the highway traveling over 65MPH the clunk becomes almost rotational and I can feel it at my feet.  The driveline is a little loud when the 4wd in engaged (traveling at speed 50MPH-ish), but it has no effect on the clunk.  
 
Nothing is visibly loose.  I slid under it with all four wheels on the ground and knocked and shook everything I could reach.  Nothing moved.  Any ideas? 
Don't just check the TB. Check the bracket that supports it at the frame. The bolts pass thru the frame with nuts near near the motor mount bracket. Also check the shock bushings top and under. Seems to be the most frequent source for noise I run into...

Sent from my LG-M210 using Tapatalk

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On 12/7/2018 at 10:14 PM, NHMJXJ said:

I slid under it with all four wheels on the ground and knocked and shook everything I could reach.  Nothing moved.  Any ideas? 

 

You're not gonna push around 3500lbs enough to actually see anything while laying on your back.

 

You need a buddy to bounce on the font end and rock the hell out of it Left/Right while you're under there. Or, slide your cellphone camera under there and film a video while you do the rocking.

 

Were your lift components installed with red Loctite?  If so, those nuts aren't gonna budge without heat, even if they need it. It can be deceptive. Your bushings break in, hardware needs to be retorqued, but the torque spec checks out because the nuts are super glued to the fastener threads. Solution is to loosen and retourque.

 

My money is on control arm bolts.

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Appreciate the help and suggestions from all of you.  This is my only trusted resource for things automotive.  I do trust my shop for general maintenance and repair, but they're not Jeep people and the collective knowledge here is unsurpassed.  Thanks again and I'll keep you posted when discovery is made.   

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Fast forward three months ... The "clunking" is more pronounced, which was actually part of the plan.  I hoped that the problem would be easier to identify. 

 

Last Friday my own shop took another look and they pointed to ball joints, which I refused to believe given they only have 10K miles on them.  Add that I do not wheel this thing, the Jeep drives straight as an arrow, no play/wander in the wheel and the tires have absolutely even wear.  I brought the XJ back to the shop that did the lift.  Their tech heard what I was talking about immediately.  We hadn't gone 100 yards.  Unfortunately they couldn't put it up on a lift, so I scheduled an appointment for today. 

 

Still no definitive reason, but what they told me was they think it's the flex joints on the controls arms.  Does this sound right/likely?  The owner of the shop said they would replace the parts free and half the labor, but qualified it with; "you'll probably have the same problem in a year".  He said all of the adjustable controls arms made for XJ's now use the same/similar flex joints.  He also added that most people install this stuff in XJs to beat the crap out of them wheeling and wouldn't be bothered by the clunk.  I guess my mall crawler is an anomaly.

 

BTW, I didn't mention anything about my shop telling me it was ball joints, but he spoke to it saying he fails vehicles on ball joints all the time, but mine would pass.

 

I know this is wordy, but I hope to get some feedback given this new info.

 

Please, thanks, Tim

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On ‎12‎/‎8‎/‎2018 at 3:16 AM, Eagle said:

I had a clunk like that in my '87 MJ. It was the left lower control arm.

 

Was it adjustable or fixed?  They also suggested I find some old  (maybe NOS) fixed control arms.

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12 minutes ago, NHMJXJ said:

 

Was it adjustable or fixed?  They also suggested I find some old  (maybe NOS) fixed control arms.

 

My '87 MJ is completely stock. It was the original factory LCA.

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Sway bar links good/tight?  I had a very similar clunking happening in this beater Ford Focus I'm working on, tracked it down to a a worn sway bar end link.  The link ends are ball-in-cup (like a tie rod end), not fixed bushings like XJ/MJ's, but it's worth a look.  I ended up finding it by unloading the suspension (jacked it up under the "frame" and not the knuckle).  When the suspension was loaded, it was nice and tight and I couldn't feel any play, but as soon as I jacked it up and let the knuckle hang free it became very obvious.

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1 hour ago, mjeff87 said:

The link ends are ball-in-cup

 

That's exactly the description of the flex joints at the end/s of the control arms.  They showed me a pic online.  The old style is fixed and has a bushing.  When I mentioned NOS, I meant after market old stock that has the fixed end, rather than the newer design with a ball-in-cup flex joint. 

 

This clunk is driving me crazy.

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I was soooo hoping that it would get so bad that someone could just point at it and say, "There's your trouble".

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20 hours ago, NHMJXJ said:

 

Still no definitive reason, but what they told me was they think it's the flex joints on the controls arms.  Does this sound right/likely?  

 

Yes, that sounds right.  Unless, we all overlooked it -- you didn't mention previously that you had adjustable control arms with heim joints.   Heim joints will make noise soon or later.  If you wanted a cadillac-quiet ride on the road, then that was the WRONG choice of component.  Adjustable control arms with solid rubber bushings at both ends would provide a much quieter and more comfortable ride.

 

20 hours ago, NHMJXJ said:

He said all of the adjustable controls arms made for XJ's now use the same/similar flex joints. 

 

This is not true.  You can find adjustable control arms with rubber bushings.  Many manufacturers provide that option.

 

20 hours ago, NHMJXJ said:

He also added that most people install this stuff in XJs to beat the crap out of them wheeling and wouldn't be bothered by the clunk. 

 

This is mostly true.  Many people who actually need the additional flex for off-road use are usually willing to sacrifice a bit of ride quality on the street.

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My objective was simply to run bigger tires, although I did explain I hadn't any plans to off-road and volunteered I wanted to keep a highway tread design..  My ignorance

of lifts is my nemesis.  I went with the package they offered and didn't know what to choose.  :(  I expected to sacrifice comfort, but thought that was the only trade-off.   

Cadillac-quiet?  I would be happy with "stock" quiet!  I'm completely satisfied with the ride quality and handling.  I just can't live with the clunk. 

 

"Heim joints" are exactly what the tech said.  I guess they're the culprit.

 

4 hours ago, DesertRat1991 said:

You can find adjustable control arms with rubber bushings.  Many manufacturers provide that option

 

Can you recommend any?    Given my initial objective, do I need _adjustable_ control arms? 

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Adjustable control arms are employed when the vehicle is lifted beyond an inch or two above stock ride height.  (They are needed to restore the proper steering caster angle.)

 

Higher lifts are generally used when tires MUCH larger than normal are fitted.  You say you want to run larger tires.  How much larger did you have in mind?

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Ball joints....ball joints will clunk, if you have had those inspected and you are assured those are not the problem........set that aside. 

 

 

Worn bushings in control arms..........those will clunk, again, if those have been inspected.......set aside. 

 

Steering link will clunk, tie rod ends..........if you are assured that is not the problem...............set aside.

 

Gear box to frame, frame can crack, steering box lose.............inspect, tighten. 

 

Lastly, and here is where I think your problem is-

 

Track bar- If hole is wallowed at axle end..........clunk. 

If fours bolts are lose at frame end..........clunk. 

If rod end at frame bracket is bad.......clunk.

If hole on frame bracket where TB rod end is mounted had wallowed.........clunk. 

None of which may be immediately obvious. Inspect closely, instruct mechanic to inspect closely. 

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On ‎3‎/‎21‎/‎2019 at 11:28 AM, Jeep Driver said:

not the problem...............set aside

 

Took the whole list and excerpts from all of you (thank you) and asked if they would run through them.  Passed in all instances except for what

they are now convinced is the problem.

 

Rough Country is fully refunding the control arms and I've ordered MetalCloak replacements.   I'll keep you posted.

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Interesting design on the Metal Cloak arms... it's not a quite a heim joint.  Something they call it a "fusion ball" instead.  Never used them myself.

 

Core 4x4 and IRO are two examples of adjustable arms that use standard press-fit rubber bushings:

 

https://www.core4x4.com/product/front-control-arm-set-tj-lj-xj-mj/

https://www.ironrockoffroad.com/product/xj-heavy-duty-front-adjustable-control-arm-set-0-65-lift.html

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