Funky clunk sound driving me absolutely insane!

[AirSpeed]

Originally Posted by El Dorado Jim

if the spring hangers are loose it could cause your noise, cut off the rivets, drive them out and install grade 8 bolts ...

I'll definitely do that but those rivets are on the drivers side, the sound is definitely coming from the passenger side. You can actually feel it on the passenger side only. It's a mystery! It will probably turn out to be something obvious and I'll kick myself when I find it.
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[67 cst swb]

***Edit*** I just reread this post and noticed its a 4x4, so disregard my suggestion below.
How is your truck lowered? If is is lowered...
I had a set of cut front coils in an old 67 years ago. they were not cut in the right location to line up with the pocket in the lower control arm. So, every time I turned the wheel past a certain point, the coil would thunk into place on the control arm. It was very noticeable and irritating.

[toolboxchev]

Check the bed bolts, I found a few making and extreme amount of ruckus. These frames do flex quite a bit.

[paul blair]

When You turn in direction of the clunk.do You feel it at the steering wheel and does it clunk more than once? Tie rod end hitting rim? Happened to me with wider rims and rod end installed wrong! Hope You find the clunk-let us know. Good Luck

[kwmech]

Try tightening the front of the leaf spring bolts

[El Dorado Jim]

have a friend turn the wheel back and forth while you are underneath it and maybe you can tell what is making the noise, is it while turning? or when hitting a bump?

[jaros44sr]

any chance it might be flywheel bolts?

[RDrancher]

Check the front axle fit at the outer axle seal, at the hub and also the axle u-joint itself. I know you're not running around in 4wd, but it's not uncommon for the front driveshaft to turn a bit and the axles turn as well. I had a bad axle fit at the seal that would bang here and there...locked the hub which centered the axle in the seal and it went away.

[garyd1961]

Just so you know mine was the exhaust pipe and didn't do it all the time. Just like you it only did it when driving. The exhaust had clearance sitting still but I guess the engine shifted enough while driving for it to hit where it went under the back side of the cab.

[AirSpeed]

Been working on this clunk for days, still no luck! Replaced the ball joints, drag link, put on new front calipers, brake pads, wheel bearings, found my front drive shaft where it connects to transfer case was missing a bolt and the rest were loose, fixed that. Tightened up every single nut and bolt under over inside and out of the truck and still have this clunk! Had a friend walk beside the truck while I drove to look and listen for the source with no luck! Had him crawl under to look just in case I was missing something but he had no luck either. Checked for cracks in the frame, none to be found. Im fairly confident the sound is coming somewhere between the rear lip of the front fender to about the middle of the cab. Checked to see if the exhaust was hitting and it's not. It's driving me insane!
It seems to happen mostly when I'm turning which makes no sense since the sound is definitely coming from further back and no where near any steering components.
It's a bloody mystery from hell! I'm just hoping whatever it is doesn't suddenly cause some sort of catastrophic failure. At least I got a bunch of maintenance taken care of that I couldn't get to all winter.

[AirSpeed]

Originally Posted by RDrancher

Check the front axle fit at the outer axle seal, at the hub and also the axle u-joint itself. I know you're not running around in 4wd, but it's not uncommon for the front driveshaft to turn a bit and the axles turn as well. I had a bad axle fit at the seal that would bang here and there...locked the hub which centered the axle in the seal and it went away.

Mine makes the sound in and out of four wheel drive, just replaced the ball joints and checked the u joints in the axle at the time, they are in good shape. Thanks though!

[paul blair]

Could there be some thing in the cowl vent pocket-lose antenna parts maybe a socket or wrench. Seems YOU checked everything else. Hope YOU find the GREMLIN.

[tutone]

Been through this with a later model GMC recently. Drove me nuts and turned out to be a wheel bearing on the drivers side. Although you felt it on the passenger side when it would clunk. Usually it is an audible clunk when you turn and transfer the weight from the opposite side. Check them both.

[AirSpeed]

Originally Posted by paul blair

Could there be some thing in the cowl vent pocket-lose antenna parts maybe a socket or wrench. Seems YOU checked everything else. Hope YOU find the GREMLIN.

No antennae, I removed it and welded up the hole when I painted the truck. The sound is definitely coming from the floor area on passenger side, I can feel it there when it happens. Checked body mounts, all tight and in good shape. Thanks for the ideas though!

[AirSpeed]

Originally Posted by tutone

Been through this with a later model GMC recently. Drove me nuts and turned out to be a wheel bearing on the drivers side. Although you felt it on the passenger side when it would clunk. Usually it is an audible clunk when you turn and transfer the weight from the opposite side. Check them both.

Thanks, I replaced the passenger side bearing when I did the ball joints last week and re packed the drivers side so I'm pretty sure there's no issue there. I'll keep searching!

[Kennuck]

I had a shock that would clunk like this. The shock mounts were fine and the shock still worked but would clunk internally. When I grabbed the shock and had my son bounce the suspension I could feel it in the shock, Replaced the shock and all was good.

[paul blair]

Can YOU check if some thing might be in the cowl vent void space down low by the kick panel.

[AirSpeed]

Originally Posted by Kennuck

I had a shock that would clunk like this. The shock mounts were fine and the shock still worked but would clunk internally. When I grabbed the shock and had my son bounce the suspension I could feel it in the shock, Replaced the shock and all was good.

That's something I haven't checked, the mounts and bushings are fine but I didn't check the shock itself, I think I'll disconnect it on one end, tie it back and see if I still get the sound. I'll report back!

[AirSpeed]

Originally Posted by paul blair

Can YOU check if some thing might be in the cowl vent void space down low by the kick panel.

I'll take a look, I do know the vent in the kick panel is clear.

[midniteblues]

Possibly a loose inner fender bolt like the big round one up in the well?

I know what your going through been there and decided too live with it till that day I actually figure it out

[AirSpeed]

Originally Posted by midniteblues

Possibly a loose inner fender bolt like the big round one up in the well?

I know what your going through been there and decided too live with it till that day I actually figure it out

I'm
Hoping the day I figure it out it's not with me in a ditch when whatever it is finally gives out!

[Husker]

Is your front driveshaft turning, could be a bad U-Joint binding as it turns.
Ron

[AirSpeed]

Originally Posted by Husker

Is your front driveshaft turning, could be a bad U-Joint binding as it turns.
Ron

I checked the front drive shaft, found the bolts were all loose and one was missing where it mounts to the transfer case, u joints are good.

[weq92f]

Check your control arm bushings.

FWIW my clunk ended up being the upper control arm bushings on the passenger side. I had checked it multiple times ( wiggle hanging tire/wheel top to bottom for movement ) and found nothing. The last time I went back to the control arms because I couldn't find anything else, it showed half an inch of movement with the wiggle test.

Strange that it was so hard to uncover. I've got new shaft kits coming and my clunk will be gone hopefully by the weekend.

-klb

[AirSpeed]

Originally Posted by weq92f

Check your control arm bushings.

FWIW my clunk ended up being the upper control arm bushings on the passenger side. I had checked it multiple times ( wiggle hanging tire/wheel top to bottom for movement ) and found nothing. The last time I went back to the control arms because I couldn't find anything else, it showed half an inch of movement with the wiggle test.

Strange that it was so hard to uncover. I've got new shaft kits coming and my clunk will be gone hopefully by the weekend.

-klb

Mine is four wheel drive, I did just replace the ball joints but it didn't fix my problem.