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You can read my original thread by clicking below, but the long and short of it is, I never could figure out a solution. But today I was able to take a clip of the rear suspension and you can see and hear what I am talking about: the clunk that both sides make when going over an imperfection in the street. Hope you can see this clip.... Thanks
PS: the sound is not so good, had to convert the file to get it to load, but the clunk happens when you see the end of the spring drop. My Movie 1aa.wmv
Sorry this will not open without first being loaded on your computer. It is safe. I'm just having all kinds of trouble.... Thanks.
You can read my original thread by clicking below, but the long and short of it is, I never could figure out a solution. But today I was able to take a clip of the rear suspension and you can see and hear what I am talking about: the clunk that both sides make when going over an imperfection in the street. Hope you can see this clip.... Thanks
PS: the sound is not so good, had to convert the file to get it to load, but the clunk happens when you see the end of the spring drop. Attachment 48298278
Sorry this will not open without first being loaded on your computer. It is safe. I'm just having all kinds of trouble.... Thanks.
Have you checked the differential crossmember bolts to the frame (2) ? Or possibly the differential mounting bolts to the crossmember (4) ? Have either of these areas been reassembled ? Is the gas tank secured as it should be ? Transmission crossmember bolts to frame on either side if automatic only I believe. Or the transmission mount itself ?
Have checked the # 3 mounting bolts behind the access door in front of the rear tire ? #4 mounts secured ? Shocks mounts were mentioned I think.
Is it at all possible when going over a bump as the leaf spring flexes could the bolt(s) to the trailing arm be catching enough to interrupt the motion causing a noise ? Just some random thoughts.
Not much else that comes to mind in the back end to me.
Hope you find the issue.
2020 Corvette of the Year Finalist (performance mods)
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i would jack it up and put the rear frame on jacks, then try and lift the tires quickly with a crow bar and see if you can make the clunk. It could be worn bushings or bad rear shocks. If it just makes the noise over bumps and not under braking I would think its the suspension and not the rear end. A loose gas tank would make sense as well. Maybe get a rubber mallet and start banging on the suspension parts and see anything is loose. Just dont hit anything that could dent or crack
Also, with it on the ground, try and lock up the front brakes and give it gas and see of the load on the suspension makes the noise.
Brother, I know you've been chasing this one for a long time. I can offer this:
If you want to pay the trip there and back, I will loan you my Chassis Ear. Very easy to use and ALWAYS finds those tough under car noises. I'll put in a new battery and ship in a USPS flat rate box. It's the ceapest way. Are you actually in Kansas? PM me your address if you're interested and I'll get you shipping cost .
Greg
Have you checked to see if you've still got all your rear alignment shims (red parts below) packed between the front of the trailing arms and the frame?
Mine were loose and gradually falling out after I first bought my '69, and found out that they had used the open-ended "forked end" type of shims, but failed to install the keeper cotter pins (blue part below) on the lower side of the shims.
I was getting the rear clunk over bumps, as well on any significant accel/de-cel inputs. Also would feel the rear end give a slight lateral shift when the noise would occur due to the extra free play at the front of the TAs.
Had a rear alignment done with new shims and pins, and been good-to-go ever since.
Just to catch everyone up, the shocks were new 1 year ago, new TRs, adjustable strut rods and half shafts 3 years ago, along with dust shields, turned rotors, brake pads, hoses and lines and rebuilt calipers. Will be checking out all the items suggested in the next few days ask time permits. Anxious to get into this. Thanks.
I was chasing a clunking noise in the rear of one of my cars. 2 shops couldn’t figure it out. I replaced the struts but the clunk remained. I was really frustrated. I realized when I pulled into my garage, the 3/4” lip at the entrance caused the noise when the rear wheels went over it. I lay on the ground and had someone push the car over the lip moving the car about 1’. I put my hand on every part I could reach and realized a control arm was the source of the clunk. Once I felt it with my hand I could see the control arm shifting in the mount.
I don’t know if you can try something like this to replicate the noise. The force on the suspension just can’t be replicated with a breaker bar, you need the momentum of the car to move things. Good luck.
I was chasing a clunking noise in the rear of one of my cars. 2 shops couldn’t figure it out. I replaced the struts but the clunk remained. I was really frustrated. I realized when I pulled into my garage, the 3/4” lip at the entrance caused the noise when the rear wheels went over it. I lay on the ground and had someone push the car over the lip moving the car about 1’. I put my hand on every part I could reach and realized a control arm was the source of the clunk. Once I felt it with my hand I could see the control arm shifting in the mount.
I don’t know if you can try something like this to replicate the noise. The force on the suspension just can’t be replicated with a breaker bar, you need the momentum of the car to move things. Good luck.
Which side was your noise on and which control arm. And what did you do to fix it, was there a control arm bushing bad, was it a crack somewhere? thanks
Brother, I know you've been chasing this one for a long time. I can offer this:
If you want to pay the trip there and back, I will loan you my Chassis Ear. Very easy to use and ALWAYS finds those tough under car noises. I'll put in a new battery and ship in a USPS flat rate box. It's the ceapest way. Are you actually in Kansas? PM me your address if you're interested and I'll get you shipping cost .
Greg
I'm thinking front differential mount as well. The bolt is #12 in this picture. The bottom bushing can look good but it's hard to see the upper bushing.
Have you checked the differential crossmember bolts to the frame (2) ? Or possibly the differential mounting bolts to the crossmember (4) ? Have either of these areas been reassembled ? Is the gas tank secured as it should be ? Transmission crossmember bolts to frame on either side if automatic only I believe. Or the transmission mount itself ?
Have checked the # 3 mounting bolts behind the access door in front of the rear tire ? #4 mounts secured ? Shocks mounts were mentioned I think.
Is it at all possible when going over a bump as the leaf spring flexes could the bolt(s) to the trailing arm be catching enough to interrupt the motion causing a noise ? Just some random thoughts.
Not much else that comes to mind in the back end to me.
Hope you find the issue.
The diff crossmember bolts to frame are very tight, but these pictures seem to show a gap (car is jacked at the differential, wheels off ground). I didn't want to lean on these bolts as I didn't want to twist them off; thinking about taking them out and replacing them while it's jacked; hopefully nothing would move. The bolts to transmission mount are all tight, bushings in good shape; the one I cannot see ' still feels soft'. The #3 and #4 mounting bolts appear in 'decent' shape, did not try to turn them though. As for the your last statement about the leaf spring I think that could be a contributing possibility but don't know how that could be changed unless I put bolts on the spring bolts above the spring ends but shouldn't have to do such a thing. I would be surprised if the shocks were bad as they are only about a year old and are Bilsteins after all.
By the way, if the transmission mount bushings needed to be replaced, how in the wild world of sports to you hole the top of that one bolt mount to crossmember; I thought I would try to tighten it but have no idea how to do it, know what I mean?
Never found a solution, rear suspension clunk
