Get under the back once is cool and start grabbing things to see what moves
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Sent from my SM-G955U1 using Tapatalk
HiSo let me describe whats happening. Ive got a 2005 Trailblazer LS with the 4.2ltr engine.It rides & sounds normal on smooth roads regardless of speed.However,when you're driving through potholes or hitting any type of bump period,you can hear a loud rattling noise near the rear.If you were to loosen a couple bolts on a metal bracket and then drive over some bumps,thats what the noise sounds like or possibly the exhaust banging against something.Ive tried wiggling the exhaust from the axle housing back,but it didnt move or hit anything.One thing I did notice though is the rubber exhaust hanger at the passenger rear.You know how they take a solid piece of rubber then cut a hole in the lower part of it (that the exhaust pipe hanger rod fits into)
then cut more sections of the rubber out?? The lower hole, on my rubber hanger,is completely torn apart so the previous owner just moved the exhaust pipe hanger rod up and slide it into the rubber cutout thats higher up on the hanger.This doesnt allow the pipe to move at idle,but if the vehicle is moving and hitting potholes,could that cause the exhaust pipe to hit a body or suspension part when the shocks compress??
Ive read that the swaybar endlinks can cause rattling noises,so whats the best way to check this??
Can I just remove the nut from the top stud of the endlinks,pull it out of its mounting hole then take the TB for a short test drive to see if the noise stops??
This noise is driving me crazy.
My rear diff fluid is due, but this sounds more like nuts and bolts in a coffee can.For me I changed my rear differential fluid with a mix of Mobil 1 synthetic 75w90 and Supertech 75w140 full synthetic. No more noise from rear.
Sorry,I know its been awhile since I posted this thread,but I wanted to update it for future reference to anyone who needs it.As a test,I removed the driver rear swaybar endlink then took it for a test drive.The noise disappeared,so I went to the parts store and bought a new end link and installed it and months later,the noise has not reappeared.So if anybody is experiencing the same symptoms I was,buy a new endlink for each side,remove the endlink on the driver & passenger side,take it for a test drive and if the noises stop,go back to the house and install the new links.If the noises are still there,once the test drive is done,reinstall the old links,return the new links to get your money back and continue trouble shooting the problem.Did you ever find out what is was rattling?
Yeah that's why I didn't replace any parts to verify if they were the cause or not.My plan was to remove one part at a time (starting with the driver rear swaybar endlink) then take it for a short test drive to listen to the results from that part deletion & fortunately,the very first part I removed was the cause.I also used this method so I would know which part was defective & the type of noise it caused for future trouble shooting.IOW- if I would have replaced 4 or 5 components,took it for a test drive and the noise had stopped,I'd be happy that the noise had gone away,but it still wouldn't have told me which part was at fault.Now I realize there are duplicates of some parts,like the endlinks/swaybar bushings/wheel bearing hub assemblys/etc, and if the part is defective on one side of the vehicle,the chances are probably high that the duplicate part (on the opposite side of the vehicle) isnt too far behind on going bad too,so if this is the case it wont hurt to go ahead &That endlink on drivers side is a bitch with the gas tank in the way. Took me twice as long for that side as it did for passenger. Replaced sway bar bushings while I was down there. Moog end links for both sides and new bushings all shipped from Rock Auto for under $60 (noise is still there) Will check exhaust system hangers and emergency brake liner next.
____________________________________________________________Yeah that's why I didn't replace any parts to verify if they were the cause or not.My plan was to remove one part at a time (starting with the driver rear swaybar endlink) then take it for a short test drive to listen to the results from that part deletion & fortunately,the very first part I removed was the cause.I also used this method so I would know which part was defective & the type of noise it caused for future trouble shooting.IOW- if I would have replaced 4 or 5 components,took it for a test drive and the noise had stopped,I'd be happy that the noise had gone away,but it still wouldn't have told me which part was at fault.Now I realize there are duplicates of some parts,like the endlinks/swaybar bushings/wheel bearing hub assemblys/etc, and if the part is defective on one side of the vehicle,the chances are probably high that the duplicate part (on the opposite side of the vehicle) isnt too far behind on going bad too,so if this is the case it wont hurt to go ahead &
replace the duplicate part too.However,for the purposes of trouble shooting this type of problem, I prefer using the 1 part removal/1 test drive method.
Some of the other parts I checked,before ultimately deciding to pull the endlink,were
the metal exhaust system shields(next to the spare tire),the hoses coming from the carbon canister,the spare tire retainer mechanism(if the rim/tire arent present or theyre present but the tire is not seated tightly against the body recess under the vehicle because the mechanism is loose),the parking brake cable/ mechanism at each rear wheel and any metal part/bracket you can find at the rear.