Chattering noise from back of motor - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Chevyman680063 · 03-13-2012, 11:39 PM

I was driving the truck around this past Sunday and it start making a noise from the back of motor/front of transmission area. It is still making that noise and it does it as soon as I crank it up. It sounds louder when it's in park and neutral. You can hear it when driving as well but only as you're slowing down or start moving b/c the sound of the motor drowns it out. The motor and trans. are 350/350. Here's a video I made of it earlier today. Thanks for the help!
https://www.youtube.com/watch?v=72JPwKZ5x8I

**jocko** · 03-14-2012, 12:08 AM

last time I had a chattering noise behind the motor, it was my spousal unit...

Now that she's gone, it's pretty quiet. Anyhoo - listened to your vid (nice job on that btw!) and I have to admit I'm stumped. My first thougt is a #7 (or #8) cyl exh gasket leak. 2nd guess would be something "rubbing" somewhere, but I can't imagine where (I would have guessed the torque converter cover plate, but you didn't have one on there). it does seem to be rpm dependent, so, has to do with recip assy or the results of it. Possibly torque conv, if it's almost time to change the fluid, i'd do it now and see if any difference in the sound (also, smell the fluid to see if it smells "burnt"). At a minimum, check the overall trans fluid level. Last but not least - on the off chance it's not runnin so good, start it at night with the lights out and look for arcing - almost sounds like that as well - could be result of plug wires going bad - or cross-wiring 2 or more plugs. Probably not much help, but others will have good ideas I'm not thinking of. If it gets louder fairly quickly - then I'd drain the eng oil and check for tiny metal flake - could possibly be the very, very beginning of a rod bearing going south.

yuccales · 03-14-2012, 08:46 AM

Maybe a cracked flexplate?

cdowns · 03-14-2012, 08:52 AM

check the flexplate and also the plastic dust shield// also check bellhousing bolts for being tight

jhwkns · 03-14-2012, 09:39 AM

Is the torque converter loose?

Meatman · 03-14-2012, 10:27 AM

Ya cracked flexplate is a really common problem and it will sound horrible.

mcbassin · 03-14-2012, 11:20 AM

Sounds like a crack in the flexplate to me. but, could be something worse??

**RenoKeene** · 03-14-2012, 02:25 PM

Broken flex plate...had to replace mine, just like yours.

HotRod C/10 · 03-14-2012, 02:29 PM

loose bolts from trans to motor....I had this happen on my 67 Camaro.

Chevyman680063 · 03-14-2012, 05:46 PM

Well I just drove it down the road and the sound wasn't as loud today as it has been the last few days but it's still there. I haven't yet had a chance to get under it to check the bolts since it's my daily driver. I hope it's only a loose bolt b/c I really can't afford anything worse than that since I was laid off and am still having no luck finding a job in this economy. I'm not really mechanically inclined when it comes to the engine/trans though just the basics...brakes, oil change, and installing engine accessories like carb, water pump, alternator, radiator, etc.

Chevyman680063 · 03-26-2012, 01:14 AM

Was able to finally get under the truck the other day and found out it was just a loose bolt thankfully. Must have come loose due to all that hp and torque.

03-13-2012, 11:39 PM	#1
Chevyman680063 Registered User Join Date: Aug 2006 Location: Georgia Posts: 850	Chattering noise from back of motor I was driving the truck around this past Sunday and it start making a noise from the back of motor/front of transmission area. It is still making that noise and it does it as soon as I crank it up. It sounds louder when it's in park and neutral. You can hear it when driving as well but only as you're slowing down or start moving b/c the sound of the motor drowns it out. The motor and trans. are 350/350. Here's a video I made of it earlier today. Thanks for the help! https://www.youtube.com/watch?v=72JPwKZ5x8I __________________ 1963 Chevrolet C10 Short Step 1968 Chevrolet C10 Short Step

03-14-2012, 12:08 AM	#2
jocko Senior Member Join Date: Oct 2009 Location: NW IN Posts: 18,118	Re: Chattering noise from back of motor last time I had a chattering noise behind the motor, it was my spousal unit... Now that she's gone, it's pretty quiet. Anyhoo - listened to your vid (nice job on that btw!) and I have to admit I'm stumped. My first thougt is a #7 (or #8) cyl exh gasket leak. 2nd guess would be something "rubbing" somewhere, but I can't imagine where (I would have guessed the torque converter cover plate, but you didn't have one on there). it does seem to be rpm dependent, so, has to do with recip assy or the results of it. Possibly torque conv, if it's almost time to change the fluid, i'd do it now and see if any difference in the sound (also, smell the fluid to see if it smells "burnt"). At a minimum, check the overall trans fluid level. Last but not least - on the off chance it's not runnin so good, start it at night with the lights out and look for arcing - almost sounds like that as well - could be result of plug wires going bad - or cross-wiring 2 or more plugs. Probably not much help, but others will have good ideas I'm not thinking of. If it gets louder fairly quickly - then I'd drain the eng oil and check for tiny metal flake - could possibly be the very, very beginning of a rod bearing going south.

03-14-2012, 08:46 AM	#3
yuccales Registered User Join Date: May 2011 Location: Northern Calif. Posts: 4,048	Re: Chattering noise from back of motor Maybe a cracked flexplate?

03-14-2012, 08:52 AM	#4
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Chattering noise from back of motor check the flexplate and also the plastic dust shield// also check bellhousing bolts for being tight __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

03-14-2012, 09:39 AM	#5
jhwkns Registered Cruiser Join Date: May 2002 Location: Las Vegas NV Posts: 2,233	Re: Chattering noise from back of motor Is the torque converter loose? __________________ I intend to live forever. So far, so good.

03-14-2012, 10:27 AM	#6
Meatman Registered User Join Date: Sep 2004 Location: Topeka, Ks Posts: 604	Re: Chattering noise from back of motor Ya cracked flexplate is a really common problem and it will sound horrible. __________________ Daily-94 K2500 350 5spd extended cab longbox Project Red Velvet-68 C20 396-th400-AC-PS-PB-all original except for the 8 track and the gun rack. Build thread>>>>http://67-72chevytrucks.com/vboard/s...d.php?t=495881 My 01 TA and 88 Formula hide in the garage. :-)

03-14-2012, 11:20 AM	#7
mcbassin Still Learning Join Date: Jul 2009 Location: Central Oklahoma Posts: 10,108	Re: Chattering noise from back of motor Sounds like a crack in the flexplate to me. but, could be something worse?? __________________ Mike "69 Short Wide" My Project 86 Silverado Landen's Project Instagram: @mcbassin My Website C/10 Club Oklahoma Facebook Group

03-14-2012, 02:25 PM	#8
RenoKeene Florida Edition Join Date: Oct 2010 Location: Fruitland Park, FL Posts: 4,055	Re: Chattering noise from back of motor Broken flex plate...had to replace mine, just like yours. __________________ 70 GMC Short Stepside "Rose"-An American Beauty: Factory 402/TH400, AM/FM, AC, Tilt, Tach, Buckets, Posi, PS, PB, 3-5 Drop, Complete Resto-Rod 67 C-20 Slant Back Wrecker "Mad Max" 67 C-10 Ratrod "Step-N-Wolf" 71 Serro Scotty Sportsman camper "Scotty" 97 LT1 Z28 "The Hornet" Link to more pics of "Rose" http://67-72chevytrucks.com/vboard/a...p?albumid=1684 Check out my "Cheap Tricks" thread and add to it if you can, lots of good info there. http://67-72chevytrucks.com/vboard/s...d.php?t=489394

03-14-2012, 02:29 PM	#9
HotRod C/10 Registered User Join Date: Feb 2012 Location: Albuquerque NM Posts: 3,054	Re: Chattering noise from back of motor loose bolts from trans to motor....I had this happen on my 67 Camaro. __________________ SOLD -77 CHEYENNE SWB, LS SWAPPED -1976 SILVERADO YUBA GOLD/NEUTRAL (2-TONE)

03-14-2012, 05:46 PM	#10
Chevyman680063 Registered User Join Date: Aug 2006 Location: Georgia Posts: 850	Re: Chattering noise from back of motor Well I just drove it down the road and the sound wasn't as loud today as it has been the last few days but it's still there. I haven't yet had a chance to get under it to check the bolts since it's my daily driver. I hope it's only a loose bolt b/c I really can't afford anything worse than that since I was laid off and am still having no luck finding a job in this economy. I'm not really mechanically inclined when it comes to the engine/trans though just the basics...brakes, oil change, and installing engine accessories like carb, water pump, alternator, radiator, etc. __________________ 1963 Chevrolet C10 Short Step 1968 Chevrolet C10 Short Step

03-26-2012, 01:14 AM	#11
Chevyman680063 Registered User Join Date: Aug 2006 Location: Georgia Posts: 850	Re: Chattering noise from back of motor Was able to finally get under the truck the other day and found out it was just a loose bolt thankfully. Must have come loose due to all that hp and torque. __________________ 1963 Chevrolet C10 Short Step 1968 Chevrolet C10 Short Step



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