Help identifying this noise - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dmw319 · 08-05-2019, 08:42 AM

So, starting a few days ago I started getting this medium pitched flappy/farty noise on the initial acceleration. It only seems to happen when its a cold start and it only happens for a few seconds at most. If I feather the gas pedal really lightly, it doesn't seem to make the noise and after a couple minutes of driving it doesn't happen at all. I think it has to be drivetrain related, but can't seem to pinpoint the source with my ears. Everything under the truck and in the engine bay seems normal. Maybe something in the transmission (its an auto) ... any ideas?

Also, in the video I just happen to be turning, but it doesn't have anything to do with that.

https://youtu.be/ttkCLqhNw-8

Astro-Balls · 08-05-2019, 02:20 PM

Exhaust leak?

dmw319 · 08-06-2019, 08:21 AM

Quote:

Originally Posted by Astro-Balls

Exhaust leak?

Could be? Its such an odd noise.

dmw319 · 08-06-2019, 08:23 AM

its also made this noise a few times recently.. its when I am slowing down its like making a clunking noise.. it happened most of the way home from work then quit. didn't make the sound this morning though.

https://youtu.be/OyWZDKhZLhk

I have taken the truck to the transmission shop and they said they couldn't find anything wrong with it.. so.. I'm still at a loss.

**Sheepdip** · 08-06-2019, 10:19 AM

Quote:

Originally Posted by Astro-Balls

Exhaust leak?

^^^^^^^^^^What He Said^^^^^^^^^^^^^^^

dmw319 · 08-08-2019, 07:50 AM

To me it sounds like a heat shield rattling.. but my truck doesn't have any

As for the brake noise... I still got nothing. I took the wheels off on both sides and everything looks normal brake/suspension wise.

geezer#99 · 08-08-2019, 08:22 AM

Did you check motor mounts or centre bearing?

dmw319 · 08-08-2019, 08:47 AM

Quote:

Originally Posted by geezer#99

Did you check motor mounts or centre bearing?

just a visual inspection and they both looked fine. ill double check this next time I'm under there!

geezer#99 · 08-08-2019, 09:10 AM

Might need to use a bottle jack to lift the motor to check the mounts.
Visual inspection doesn’t always work well.

cornerstone · 08-08-2019, 09:23 AM

Long bed truck? That clunking sound would the center bearing, my guess. It seems to be on deceleration only.

dmw319 · 08-09-2019, 08:15 AM

Quote:

Originally Posted by geezer#99

Might need to use a bottle jack to lift the motor to check the mounts.
Visual inspection doesn’t always work well.

yep. good call, will do!

Quote:

Originally Posted by cornerstone

Long bed truck? That clunking sound would the center bearing, my guess. It seems to be on deceleration only.

shortbed. ill have to check it. seems odd it would only have intermittently though, right? I feel like once it starts to go it would just get worse but it hasn't happened the past two days.

dmw319 · 10-09-2019, 08:29 AM

So.. I found/fixed one of the sounds today. It was the transmission flex plate cover. I don't know why it was vibrating and making that buzzing/farting noise.. but when I pressed up on it just barely, the sound went away. It wasn't loose or anything. So... I just removed it and the sound is gone completely.

The braking clicking/clunking hasn't happened in a few months so I'll just worry about that if I continue to hear it.

Thought I'd post a follow-up in case this happens to anyone else.

How important are these covers anyway? Figured I could just leave it off permanently.

08-05-2019, 08:42 AM	#1
dmw319 Registered User Join Date: May 2012 Location: Raleigh, NC Posts: 639	Help identifying this noise So, starting a few days ago I started getting this medium pitched flappy/farty noise on the initial acceleration. It only seems to happen when its a cold start and it only happens for a few seconds at most. If I feather the gas pedal really lightly, it doesn't seem to make the noise and after a couple minutes of driving it doesn't happen at all. I think it has to be drivetrain related, but can't seem to pinpoint the source with my ears. Everything under the truck and in the engine bay seems normal. Maybe something in the transmission (its an auto) ... any ideas? Also, in the video I just happen to be turning, but it doesn't have anything to do with that. https://youtu.be/ttkCLqhNw-8 __________________ 1970 Chevy C-10 Stepside My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=528167 Last edited by dmw319; 08-08-2019 at 08:53 AM.

08-05-2019, 02:20 PM	#2
Astro-Balls Registered User Join Date: Feb 2019 Location: Nor Cal Posts: 822	Re: Help identifying this noise Exhaust leak? __________________ 1968 C20 Fleetside 396 4sp PS PB AC CST . https://www.youtube.com/watch?v=RWK8GgWD4uA

08-06-2019, 08:23 AM	#4
dmw319 Registered User Join Date: May 2012 Location: Raleigh, NC Posts: 639	Re: Help identifying this noise its also made this noise a few times recently.. its when I am slowing down its like making a clunking noise.. it happened most of the way home from work then quit. didn't make the sound this morning though. https://youtu.be/OyWZDKhZLhk I have taken the truck to the transmission shop and they said they couldn't find anything wrong with it.. so.. I'm still at a loss. __________________ 1970 Chevy C-10 Stepside My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=528167 Last edited by dmw319; 08-06-2019 at 09:44 AM.

08-08-2019, 07:50 AM	#6
dmw319 Registered User Join Date: May 2012 Location: Raleigh, NC Posts: 639	Re: Help identifying this noise To me it sounds like a heat shield rattling.. but my truck doesn't have any As for the brake noise... I still got nothing. I took the wheels off on both sides and everything looks normal brake/suspension wise. __________________ 1970 Chevy C-10 Stepside My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=528167

08-08-2019, 08:22 AM	#7
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: Help identifying this noise Did you check motor mounts or centre bearing?

08-08-2019, 09:10 AM	#9
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: Help identifying this noise Might need to use a bottle jack to lift the motor to check the mounts. Visual inspection doesn’t always work well.

08-08-2019, 09:23 AM	#10
cornerstone Registered User Join Date: Apr 2014 Location: Azle,Texas Posts: 2,248	Re: Help identifying this noise Long bed truck? That clunking sound would the center bearing, my guess. It seems to be on deceleration only. __________________ Brian 1972 C10, "Loyd", LWB to SWB, 5.3, L83/6L80e, 4:11 Tru Trac, Air Ride, VA, DD, 20" Coys, 4 wheel disc, A quick LS swap turned into a 6 year frame off resto-mod.

10-09-2019, 08:29 AM	#12
dmw319 Registered User Join Date: May 2012 Location: Raleigh, NC Posts: 639	Re: Help identifying this noise So.. I found/fixed one of the sounds today. It was the transmission flex plate cover. I don't know why it was vibrating and making that buzzing/farting noise.. but when I pressed up on it just barely, the sound went away. It wasn't loose or anything. So... I just removed it and the sound is gone completely. The braking clicking/clunking hasn't happened in a few months so I'll just worry about that if I continue to hear it. Thought I'd post a follow-up in case this happens to anyone else. How important are these covers anyway? Figured I could just leave it off permanently. __________________ 1970 Chevy C-10 Stepside My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=528167



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