Suspension Issue

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Jun 6, 2019
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Cali, USA
Hey Guys, '03 Suburban, new Munroe OESpectrum shocks all around. There is a squeak and clunk in the rear suspension that the mechanic can't figure out. The issue is that going in/out of driveways, rough roads, speed bumps, there is a metal on metal rubbing sound, like bad bushings and sloppy leaf springs. and a clunk/clank like leaf spring slap. The thing is, the Burb doesn't have leaf springs and there are no signs of loose or wear in the suspension components. The mechanic had the thing for two days and couldn't figure it out. I went back in and went on a test drive with them and couldn't get the clunk/clank, but was able to replicate the squeak/rubbing sound. They still couldn't find anything. It occurred to me after the test drive that the Burb normally carries around 300 to 400 pounds in the cargo area, so I put the weight back in when I got the truck back and the clunk is back. So, it's obviously weight related, but that doesn't explain why there are no wear indicators. The mechanic said they can't see anything and can't get anything to move when it's up on the lift. The mechanic has checked the shock attachment points, trailing arms, spring cups, etc., to no avail. With the amount of noise this thing makes, there should be something obvious, but it's hiding!! Any thoughts?
 

01rangerxl

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Yes, consider other things that might move or jiggle. Heat shields, doors, etc. Noises often aren't what they seem to be at first.
 

A_Spruce

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The noise is definitely outside the vehicle (jack stowed inside rear compartment). I want to say that it's definitely suspension related, since it's heard when traversing rough road, though primarily speed bumps and in/out of driveways. It is not a bang like the exhaust hitting somewhere, it's a loose bolt or bad bushing kind of bang.
 
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Check the drive shaft and u-joints, remove it and lube the splines going in to the transmission with a light coat of chassis grease. Some models also have zerk fittings so grease them too. Apply spray lube liberally to all the suspensions bushings. I assume the mechanic already checked hub bearings etc.
 

A_Spruce

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Noise was present before shocks were replaced. New shocks helped, but did not cure the issue. I'm going to assume that the mechanic went over the driveshaft and each contact point of the suspension. I had the diff serviced and they inspected inside the cover during the service. They were also supposed to do a chassis lube along with the diff service.
 
Joined
Jan 21, 2011
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I would check all the suspension bushings and sleeves. They can get a bit cockeyed after years of use and make odd sounds in certain situations but not in others. I'm sure this is irritating, the burb sounds cherry so good luck finding the noise smile
 

A_Spruce

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She definitely has good bones and has been great for the 18 months I've had her. Though, as with all aging vehicles, she needs a little more TLC than something a bit newer. I will be taking her back to the mechanic for another test drive with all the weight in her. I suspect that if we get a couple guys bouncing on the bumper that we can get her to squeak and thump enough for another guy under the vehicle will be able to locate the source of the noise.
 

A_Spruce

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A quick update: I crawled under the back end of the Burb and shot some WD40 at all the pivot points and spring cups. The harsh ride and associated noises have virtually disappeared, but I still have a significant metal on metal rubbing noise. I have not had a chance to go back under and lube everything again, hopefully I can do that this weekend. I'm half tempted to pull the bolts at the pivot points, both for inspection and lubrication. The metal on metal rubbing noise also has a knock to it at times, as if it were a loose or severely worn bolt or bushing. The thing is, there's no shiny spots indicating such slop and play. That is part of what stymied the mechanics, there's no movement that they can detect, up on a lift with prybars, visual inspections, what-have-you. They also couldn't replicate the noise, even with my help, which I figured out was due to the lack of the usual weight that is normally carried. I was planning on loading her back up and go for a ride with the mechanic, but time just isn't available for that right now.
 
Joined
Dec 17, 2011
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397
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Northern NJ
Give some consideration to the body mounts. There are quite a few and some can be prone to rot out the central bolt. I've got a bad one on the right center on my '02 Tahoe, though it manifests itself with more shake than noise.
 
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