Clunking noise when going over potholes (1 Viewer)

Joined
Aug 24, 2022
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Clemson, SC
Need some advice (other than "turn up your radio" Haha). I have a clunking noise in my 97 80 Series when I go over potholes. The noise was there when I bought it, but initially I wasn't too concerned about it because I assume that the new lift and all new suspension parts would take care of the noise - however the new parts didn't fix it. I have an Icon 3" lift - stage 3. Front and back sway bar end links and sway bar bushings were replaced (OEM Toyota). I even removed the rear sway bar temporarily to see if that was it - no luck. I noticed that 2 exhaust hangers were rotten, and I was hopeful that replacing those would fix it, but it didn't (also replaced with with OEM Toyota exhaust hangers). I removed the spare tire (didn't help), then I removed the spare tire holder (didn't help). I've confirmed that the noise is coming from outside the vehicle -not inside. If I had to say it sounds like its coming more from the right hand side, and it sounds like its coming from the rear? Maybe the middle, but pretty sure that it's not the front? I do not hear any driveshaft clunk when I'm accelerating, so I don't think this falls in that category. Is it possible that it's the exhaust? Everything seems tight. When I bang on the exhaust I can't make it reproduce the same sound. Also, when the vehicle is in park we've tried to jump up and down on the rear bumper, but it does not make any sound. Same thing with jacking up the vehicle and then dropping it quickly. No sound. The exhaust looks like it may be original (25 years old), so it may need replacing, but I'd like to rule everything else out, or at least find a way to confirm that the exhaust is the problem before I change it out. What am I missing? Any thoughts? Thanks in advance.
 
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Feb 12, 2021
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New Idria 95043
Need some advice (other than "turn up your radio" Haha). I have a clunking noise in my 97 80 Series when I go over potholes. The noise was there when I bought it, but initially I wasn't too concerned about it because I assume that the new lift and all new suspension parts would take care of the noise - however the new parts didn't fix it. I have an Icon 3" lift - stage 3. Front and back sway bar end links and sway bar bushings were replaced (OEM Toyota). I even removed the rear sway bar temporarily to see if that was it - no luck. I noticed that 2 exhaust hangers were rotten, and I was hopeful that replacing those would fix it, but it didn't (also replaced with with OEM Toyota exhaust hangers). I removed the spare tire (didn't help), then I removed the spare tire holder (didn't help). I've confirmed that the noise is coming from outside the vehicle -not inside. If I had to say it sounds like its coming more from the right hand side, and it sounds like its coming from the rear? Maybe the middle, but pretty sure that it's not the front? I do not hear any driveshaft clunk when I'm accelerating, so I don't think this falls in that category. Is it possible that it's the exhaust? Everything seems tight. When I bang on the exhaust I can't make it reproduce the same sound. Also, when the vehicle is in park we've tried to jump up and down on the rear bumper, but it does not make any sound. Same thing with jacking up the vehicle and then dropping it quickly. No sound. The exhaust looks like it may be original (25 years old), so it may need replacing, but I'd like to rule everything else out, or at least find a way to confirm that the exhaust is the problem before I change it out. What am I missing? Any thoughts? Thanks in advance.
the exhaust muffler is really heavy, you will need to lie on your back and push up on it with your legs/knees. but the exhaust rubber isolators do wear out and become separated. I had a loud vibration noise at stop lights in drive due to them. im sure someone will chime in with some suspension bushing and or shock recommendations
 
Joined
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Olathe, KS, USA
Your front driveshaft could be contacting a sway bar.
Your driveshafts should have the slip yoke to the FRONT of the vehicle on both.
You may have a spring coil contacting part of the frame.
You could have a panhard bar bushing that is bad and making noise.
 
Joined
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Messages
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Location
Clemson, SC
the exhaust muffler is really heavy, you will need to lie on your back and push up on it with your legs/knees. but the exhaust rubber isolators do wear out and become separated. I had a loud vibration noise at stop lights in drive due to them. im sure someone will chime in with some suspension bushing and or shock recommendations
I replaced 2 of the exhaust rubber isolators, but that didn't solve the problem. I'll try to push up harder on it and see if I can reproduce the sound. Thanks
 
Joined
Aug 24, 2022
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Location
Clemson, SC
Your front driveshaft could be contacting a sway bar.
Your driveshafts should have the slip yoke to the FRONT of the vehicle on both.
You may have a spring coil contacting part of the frame.
You could have a panhard bar bushing that is bad and making noise.
The only thing that I can tell has contacted in the past is the exhaust as it goes over the rear axle. I'm assuming they don't come semi-flattened out from the factory. My guess is that happened with the previous owner when he had worn out springs and old shocks and let it fully compress? I would hope that it's not still making contact now that I have new springs and shocks, right? I hadn't thought about the panhard bar bushings. I'm waiting on a rear panhard lift bracket from Delta so I'll replace those bushings when I install that. Thanks for the ideas
 
Joined
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LUGOFF, SC
Last time I had a clunk like this it was a bad shock bushing and the shock was moving around in its mounts, but only when I hit a speedbump, pothole or other sudden suspension movement.
 
Joined
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Olathe, KS, USA
The only thing that I can tell has contacted in the past is the exhaust as it goes over the rear axle. I'm assuming they don't come semi-flattened out from the factory. My guess is that happened with the previous owner when he had worn out springs and old shocks and let it fully compress? I would hope that it's not still making contact now that I have new springs and shocks, right? I hadn't thought about the panhard bar bushings. I'm waiting on a rear panhard lift bracket from Delta so I'll replace those bushings when I install that. Thanks for the ideas
The exhaust is actually flattened in the area above the axle from the factory. It's between the frame and body, so it's not like it's going to get mashed due to a collapsed spring.
 
Joined
Jan 19, 2005
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South west utah
Check any suspension bushings that were not replaced. Ie rear control arm bushings, front radius arm bushings, and pan hard bar bushings.

Also check your body mounts.

To check the exhaust sit down or lay down under the vehicle and kick the tailpipe.

Check the motor mounts and tranny mounts.

Check the supports for the tailgate, they can get loose and make weird noises.

My guess is your clunk is coming from the front radius arm to frame bushings.
 

CPACruiser

Supporting Vendor
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PA
All this speculation...put in on a lift and push and pull on all suspension and moving parts...then you'll most likely have your questions answered.
 

mudgudgeon

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Across the pond, and upside down
I'm assuming they don't come semi-flattened out from the factory.

You assume wrong.
That is a TuRD special.
Factory fitted high performance goodness.
It's what gives all the 80 series engines that neck snapping performance . . .










or not.
 

mudgudgeon

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Back to speculating on the subject at hand,

Check for frame cracks around the steering box, and panhard rod brace.

Another maybe is slotted holes in the radius arm brackets on the front diff housing. Loose bolts here can eventually cause holes to wear into an elongated hole.
 
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Jan 12, 2016
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Australia
check the rod ends on the relay rod in case the one that the steering damper is connected to has its adjustment lock nut leaning on or very close to the steering damper. As the suspension moves from the potholes / bumps can cause a clunk if too close or worn relay rod ends
 
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Joined
Oct 27, 2015
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Westminster, Colorado
I have, had this issue. For me it was the control arm bushings. I replaced them with Beck Arnley's...and yeah i now have to do the job again in less than 10k miles. If they havent been replaced before with their age it wouldnt hurt to do so.
 
Joined
Aug 24, 2022
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Clemson, SC
I appreciate all the replies. Yes it's a bunch of speculation (as someone mentioned), but that's exactly what I asked for. This gives me a ton of additional ideas that I hadn't thought through yet. Looks like my weekend will be busy!!
 
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Jun 8, 2007
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Houston
All control links are tight, shock mounting bolts, shock reservoirs, sway bar end links, sway bar bushings intact? I have a clunk on mine but it's due to worn out rear bumper swingout bushings.
 
Joined
Aug 24, 2022
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Clemson, SC
MYSTERY SOLVED, but this is an odd one, so I'm not sure if it will be something that will help out other Mudders. I started going through the list compiled by you fine folks and was checking everything, but still not finding the source of the noise. Then I started to expand my search and started banging on everything (mostly out of frustration). I always felt like the noise was coming from the right rear so I started banging on the right rear caliper, rotor, and dust shield - and bingo I found it. My initial thought before I tore into it was that one of the springs for the emergency brake shoes must have broken and allowed the shoes to flop around inside the rotor, however, it was even dumber than that. The previous owner had allowed an old brake pad to slip between the back of the rear right rotor and the dust shield, and never bothered to get it out. How lazy is that? The caliper had both brakes pads, so this must have happened in a previous brake change. Maybe they didn't see that it fell out of the caliper, maybe they saw it and assumed that it would fall out on it's own (stupid and dangerous), maybe they didn't want to take the caliper bracket and rotor off, or maybe they just didn't care? In all fairness, maybe I should have called this a "clank" rather than a "clunk", but can anybody honestly say that they would have said "check to see if the PO left a brake pad between the rotor and the dust shield" hahaha. All the advice was still good advice though: I still plan to replace the rear bushings to the front radius arms (at the frame) since I already replaced the front 2 at the axle with castor correction bushings, and I still plan to replace the rear panhard bar bushings once I get the Delta panhard lift bracket. THANK YOU ALL

Leftover brake pad.jpg
 
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Mar 22, 2018
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coloRADo
I’m glad you followed up with this. It would have never crossed my mind and it would have driven me crazy! Good find!
 

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