Knocking noise in the rear

T4RFool

T4RFool

New member
so i've had this knocking noise in the rear of my 4runner every time i go over a bump for quite a while now and i cant seem to figure a solution to fix it. i think i've narrowed it down to the rear body mount on the drivers side. i have a 1" body lift but the noise was present before that. the noise goes away if i tighten down the bolt holding that body mount and bushing in place but after going over a few bumps the noise come back again... its really frustrating. i have tried everything i can think of, threadlock, locking washers, locking nut, combination of all of the above and nothing seems to keep it from spreading back apart.:ybrick:
 
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tried that lol its the grade 8 bolt that came with the toytec 1" body lift. i picked up another one at lowes, same length and grade to see if that would work
 
T4RFool said:
tried that lol its the grade 8 bolt that came with the toytec 1" body lift. i picked up another one at lowes, same length and grade to see if that would work
Click to expand...

hahaha from your original post it sounded like you tried everything but replace the bolt lol hmmmm.... yes maybe the sway bar... just remove it altogether. See if that works..... also have you checked your rear shock bolts? The ones on top might be a little loose... that could easily cause knocking.
 
rear sway bar is something new that i havent tried, but it sounds like a plausible cause, i will give that a shot and see what happens
 
i went out and checked out the sway linkage, they seem pretty shot to me, i got to lookin at them and i might have to take a grinder to them just to remove, they're pretty rusted, gonna go blast it with some PB later and let it set over night and try to remover them tomorrow. the one on the driver side did have a clicking noise when i moved the sway bar up and down, it wasnt a very pronounced clicking or knocking noise but im going to remove the endlinks anyway and see if that really is the source
 
if i can manage to get them disconnected without the use of the grinder i'll do one side at a time to see if the noise goes away
 
If its not the sway bar links, do you have a hitch in? It took me fore ever to figure out where my big clunk was coming from when i went over a speed bump. turned out just to be the hitch. also check to see if you spare tire is loose.
 
i have no hitch in, i took everything out of the trunk area, no hitch, no equipment, no spare tire, nothing lol had the wife drive it around while i rode in the trunk to figure out where the noise was coming from better
 
so i removed my rear sway bar completely and the noise is still present, i thought the sway bar removal would take car of the problem and it did seem like it for a short while and then the noise returned....:ybrick:
 
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i gave the undercarriage a thorough washing today and gave everything a thorough look over and still cant figure it out... WTF!!!
 
It could be your rear body mount (although my 1" BL has never made any noise), but that seems unlikely to me since the noise came back so quickly after you tightened the bolt. Makes me wonder if that was the issue or if it just happened to not clunk on the first bumps you tried it on. I've found that noises just love to disappear right after you mess with something unrelated and just when you think you figured it out, the noise is back, DOH!

Did you check the body bolt to see if it was loose again after the noise came back? Did you check the bolt on the other side? I'm thinking if you cranked down on one, it could have loosened another. But all that aside, I doubt it's your body lift because I've never had any noise with mine and I've personally never heard anyone having that issue on a 3rd gen at least.

So...
I would put one of your feet on top of a rear tire and sorta move your body back and forth so it rocks the truck. Have a buddy lay under the truck and listen. Or better yet, you listen and have your buddy rock the truck. I mention this "put your foot on the tire" technique because it works better than jumping up and down or rocking the truck with your hands because the motion is coming from the tire like it would naturally - as opposed to rocking the body with the motion coming from above. Find a spot where it will make the noise when you drive pretty slow. Then have your buddy stand next to the bumps so he can try to make sure that it's coming from the rear. Sound can bounce around down there and it's hard to know for sure when you're inside the truck.

Look at the panhard bolts and the bushings too. Just the other day, Driffter33 and I found his clunk with the way I described and it was the panhard bushings/mounts.
 
One more thing to check that I didn't see mentioned... your upper shock mounts. Check out that nut up top on both rear shocks and make sure it's snugged down nice and tight. I had a similar noise after I lifted my 'Runner and it turned out I hadn't tightened that nut on the driver's side rear shock quite enough.
 
i checked out the shock mounts yesterday while i was under there removing the rear sway bar, they seems pretty solid, the bushings were still in good shape.

i dont think its the body mounts either because the noise was present before i installed the BL but i couldnt think of anything else. i have checked out the panhard bar, gave it a good grab and shook and banged on it, it seemed pretty solid.

i dont think i'll be able to get under there today to look at stuff like the panhard bar. colo springs is having some weather today and im currently without garage for a little bit... sad day :moping:
 
alright, so i went out and did some more checking. checked the panhard bar and bushings, control arms and bushings. i really tightened down the body mount bolt and checked all the others. im starting to think that may be something in the body knocking around. the only thing that i can think of on the drivers side is the little vent thingy and the gas filler up but what could be knocking around in there?
 
T4RFool said:
alright, so i went out and did some more checking. checked the panhard bar and bushings, control arms and bushings. i really tightened down the body mount bolt and checked all the others. im starting to think that may be something in the body knocking around. the only thing that i can think of on the drivers side is the little vent thingy and the gas filler up but what could be knocking around in there?
Click to expand...

Hmmm, I have replaced my filler pipe, and there really isn't much there, and it probably isn't moving around.

I had a knocking that I mostly heard when turning or hitting bumps, and it turned out to be the panhard like Brian said. Be sure you are tightening the panhard and UCA/LCA nuts to spec, because that sounds likely to me. Also check the driveshaft bolts. It sounds like a suspension issue.
 
these components are a little rusted under my rig. if it is the panhard bar like you guys have mentioned, if i try to remove the bolts on these components im worried that i'll probably snap the bolts. where can the replacement bushings be found. finding a new bolt is easy lol.

i figure that since i cant figure out the noise, im just gonna buy new bushings for everything just to be sure cause this noise is driving me nuts. :redbrick:
 
ok, i figured it out, finally!!!! now to fix it. it was the body bushing in the rear as was suspected in the beginning, here a sweet video showing you what the cause of the noise is:
<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/dA6knDh0d-E" frameborder="0" allowfullscreen></iframe>
 
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