Need help! Sounds like an empty soda can...

[AceX]

Funny thing happened to me about 10 minutes ago. I went over some speed bumps by my house and as soon as I'm over the first one there's this really wierd noise coming from the truck like there's an empty soda can rolling around somewhere. It's really touch and go too. It isn't happening @ idle, under braking, acceleration, nothin. Just randomly while driving. Truck is parked until I can fix this.

Best I can tell is that it isn't coming from the engine bay, but other than that, I'm stumped. I'm hoping one of you guys can help me out here.

All the vitals check out too. Oil Press., temp., and voltage.

[Oldschool82]

I don't know what kind of rims you have, but I used to have an old 70 mustang with saw blades on it and one of them had a center cap that did not fit snug. When I would go down the road it would rattle like the can noise you described. The speed bump may have loosened one or more of them. Just go around and bump them with your hand and see if one is loose. Just an idea, hope that is all it is.

[old Rusty C10]

could a sway bar link be broken? something loose under the chassis?

[f.monroe]

Is it a one piece drive shaft or does it have a carrier bearing . I have seen the metal ring come loose and make a tin sounding noise . It is probably more likely a sway bar bushing or shock mount or something in the front . I usually let my wife drive it while I walk along side so I can locate the noise .
Frank

[AceX]

Gonna see if I can get my room mate to led a hand tonight. There's nothing dragging on the ground (that's the first thing I checked, and my suspension is still in good shape.

I checked anything and everything I have modified first. All the suspension bolts, are good, steering, brakes, wheels have tight lugs and spinner caps are secure and good.

It's not something that is hard to notice either. Its pretty loud, but random, making it hard as hell to catch and even harder to reproduce...

It's a one piece shaft as well.

[sdavid]

Fan coming in contact with the shroud?

[pig rig]

also check the trans inspection cover they make all kind of noise when they finaly fall off also if you have a clutch fan check it out they start out as a random sound

[AceX]

Originally Posted by sdavid

Fan coming in contact with the shroud?

It would be more consistant if it was the fan. Plus I checked it, still good.

I'll see if I can get the fan clutch to act up.

[special70gmc]

how bout those huge heat shields above the cats ive had one of them give me some trouble in the past..

[f.monroe]

I would jack it up and spin one wheel at a time . A dast cover that falls off the spindle can roll around inside the centercap of the wheel .
Frank

[grinch4om]

does it rotate ? rythmic at all?if rythmic, check anything that spins...if it only happens with bumps, get a light rubber mallet and get on a creeper (with the keys in your pocket) and tap around underneath, rocks in the cat covers, rock in the dust shield under the torque converter, front brake dust shield loose etc...

[heavychevy79]

Originally Posted by grinch4om

does it rotate ? rythmic at all?if rythmic, check anything that spins...if it only happens with bumps, get a light rubber mallet and get on a creeper (with the keys in your pocket) and tap around underneath, rocks in the cat covers, rock in the dust shield under the torque converter, front brake dust shield loose etc...

"with keys in your pocket" good advice as always. Wearing a big coat with lots of adjustment strings is a good idea as well while your on the creeper.

[westie 666]

The same type of thing happened to me, turned out the muffler was contacting the drive shaft, look for a silver ring around the shaft.

[83burban]

How about the heat shield on the exhaust manifold?

[3r!c84]

center cap? mine did that when it was loose

[77shortybawx]

What kind of mufflers do you have? the kid that owned my truck before me had an identical problem. It turned out that the baffle thing inside the glasspack actually broke loose and was rattling around. It sounded like he was dragging a couple empty cans around behind him, but i suppose if you do not have glasspacks that would not be the problem.

[dammitmitchell]

gentlemen
when i hear this noise i work in this order..
"hubcaps" center caps.. CHECK THE heat shield over any catalytic converter or muffler parts....
spedometer cable (is it clamped or whackin something)
and then check for loose trim etc...

[AceX]

I talked with a buddy of mine who had this exact same problem a couple month back. Thinks it's the cat.

I have completely nut/bolted the suspension and chassis. I'll bet that this thing is more tied down than when it left the factory...

Still making the dam noise, so I'm going to the guy who built my exhaust tomorrow to see if we can't build a cat-delete pipe. At the very least it will eliminate one of the potential culprits.

[dammitmitchell]

well you can tell easily by touching the cat,
but unless there is damage to the underside of your cat itself there is not likley damage inside the cat, honeycomb is a resilient structure and take alot of damage...
check the cat shield before you spend money the spot welds on the heat shield (top side usually) are easily broken with vibration

good luck

[AceX]

Found out what it was (interesting story on how I found out). It's a fly wheel bolt. It completely backed out and is clanging around inside the bellhousing. The truck is cooling down right now so I can tear it apart...

[dammitmitchell]

crap...
well dang dude!
good find

[Dapper Dan]

I'll bite, how did you find that?

[badblu97]

Originally Posted by Dapper Dan

I'll bite, how did you find that?

Im in as well.....

[pig rig]

aww man you've got a handle on it I was hoping every one was still grasping at straws so I could tell you to check the coolent level in you water cooled muffler bearings

[AceX]

So, I took the truck into my exhaust guy and of course it wasn't making any unwanted noise. It never does around the mechanic...

Well, we put the truck on a lift, checked everything again, double checked, and then patched up a weld on the exhaust and reinforced a hanger. Now with the exhaust buttoned up, we bring the truck down, start it up, and back it out. Everything is just fine.

As soon as the truck moves forward, it starts making horrible nightmarish noises like never before as if to say "WAIT! I wanna go back!"

My buddy Scott pulls the truck back up on the lift, pulls the flywheel cover, and sure enough, one of the 4 bolts is completely missing, but it isn't sitting in the pan... Great...

We bolt the pan back on, and limp the truck back home, park it, and wait for it to cool down.

I tear into the god forsaken bell-housing and find what could best be described as a mechanical murder scene. This bolt decided to go off the deep end, and backed itself out all the way, then went on a crime spree, raping and pillaging its way around inside the flywheel's home. It MESSED UP the starter, mugged the dust cover, and maimed the flywheel itself.

Now, I need a new pan (cover), new bolts (which were a nightmare to get ahold of), and a new flywheel and because I don't get more than 1 day off in a week, I have to have a shop do the work on the truck now.

On top of all this crap, I got a call from the CARB State Ref (they are the smog gurus) about my motor swap I'm planning and he told me that it will be so much work that it's not worth it. He was telling me that for the visual inspection, that the distance between the cats and the manifolds has to be EXACT. The EVAP system has to be from the original vehicle, and best of all, I have to use the transmission that the motor came with. Problem is that the tranny I have is AWD... So now my motor swap is pretty much trashed. Great...

My day was awesome.