# Rattle coming from bell housing area.



## jtwoods4 (Dec 22, 2011)

69 gto. 4 speed manual. Noticed a rattleing sound coming from the area around the bellhousing. Happens most when engine is at idle. Any ideas?

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## jtwoods4 (Dec 22, 2011)

I forgot to mention that the car drives fine and there are no issues with performance. But since the sound appeared I have a feeling something is about to go wrong.

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## jtwoods4 (Dec 22, 2011)

I also forgot to mention that I just replaced the heater core because it busted in antifreeze filled up the passenger floorboard. The rattling started happening in the bell housing area the day or so before I noticed the busted heater core. Could antifreeze on the clutch disc cause this rattle sound?

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## Eric Animal (Oct 28, 2007)

sounds like a bad throw out bearing, or crank bushing.....the bolts that hold the neck on the tranny could be loose,,,,the tranny could need lube.


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## Eric Animal (Oct 28, 2007)

JT, YES, if anti freze was getting on the clutch, throw out bearing, etc...it COULD have caused some rust/lack of lube....


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## jtwoods4 (Dec 22, 2011)

I think anti freeze is non corrosive, will not cause rust. But at least a gallon leaked out of the heater core and I am sure some leaked into the bell housing. 

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## ALKYGTO (Mar 29, 2010)

Eric Animal said:


> sounds like a bad throw out bearing, or crank bushing.....the bolts that hold the neck on the tranny could be loose,,,,the tranny could need lube.


:agree TOB


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## jtwoods4 (Dec 22, 2011)

Ok thanks guys, I will pull the tranny and inspect.


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## geeteeohguy (Feb 2, 2008)

Before you pull the trans, check the mechanical clutch linkage. It can wallow out at the Z bar connection and at the clutch fork, and get loose and rattle around. It should have a spring on it to help prevent the pushrod from rattling against the clutch fork...just a quick look is all you need!


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## jtwoods4 (Dec 22, 2011)

Good idea! I hope that's the problem, would be a much easier fix.


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## Eric Animal (Oct 28, 2007)

True, and the antifreeze, while not corrosive, could have washed away any lube ...If the TOB goes bad and wont turn freely, it could EASILY ream out the clutch fork....E


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## jtwoods4 (Dec 22, 2011)

Update. I ran down to the drug store and bought a blood pressure kit that included a stethoscope for 20 bucks. I came home and cranked the car and let it idle. I then put the stethoscope on and put it to the valve cover, the rockers, etc. sound fine. I then crawled under the car and put the stethoscope to the bellhousing... just the normal gear turning sound. I put it to the transmission case, again, normal gear turning sound. I then put it to the passenger side header and bam, the sound was in my ear.

So I found where the rattling sound is coming from. I inspected the header to see if it was contacting with the frame anywhere. No contact anywhere.

Oh well, atleast the stethoscope saved me the trouble of dropping the tranny. Now I just need to find the cause of the rattle!


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## rickm (Feb 8, 2012)

jtwoods4 said:


> 69 gto. 4 speed manual. Noticed a rattleing sound coming from the area around the bellhousing. Happens most when engine is at idle. Any ideas?
> 
> Sent from my LG-P999 using AutoGuide.Com Free App


could be a simple case of clutch linkage out of adjustment or maybe a worn out clutch fork ball stud causing rattle (release bearing not centered). coolant wouldnt have anything to do with it. also check return spring. would not pull tranny right away. use the inspection cover. rickm.


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## BearGFR (Aug 25, 2008)

When it's rattling, can you make the sound change by slowly applying pressure to the clutch pedal? If it does then that's evidence the problem is somewhere in the linkage.. anywhere from the pedal up to and including the throwout bearing.

Ooops - just read your update about it being in the header. Disconnect the pipes at the collector and see if you can spot something loose in there?

Bear


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## 1970 Lemans (Jul 25, 2009)

jtwoods4 said:


> 69 gto. 4 speed manual. Noticed a rattleing sound coming from the area around the bellhousing. Happens most when engine is at idle. Any ideas?
> 
> Sent from my LG-P999 using AutoGuide.Com Free App


My 70 has an automatic, TH350. Sometime back it also made a rattling (actually a harmonic clang or tinny knock) from the bell housing area, but only at idle. FWIW, it turned out to be a cracked flex plate ... just saying.


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## jtwoods4 (Dec 22, 2011)

Turns out the sound is coming from the passenger header rattling. The rattle is where the 4 header pipes converge to connect to the 3 inch exhaust pipe. The headers pipes get very very close together there and are actually rattling against each other. Not sure how to fix unless I wedge something in the very small space between 2 of the pipes.


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## Rukee (Feb 8, 2007)

It must be cracked or something then, those tubes should all be welded to the collector.


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