whistling sound... HELP - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chev74 · 02-08-2008, 01:19 AM

Took about a 150 mile trip the other day and got to a stoplight and started to hear a whistling/chirping sound. My first instinct was a vacuum line, but then i realized that it was increasing with rpm, so wouldnt a vacuum line whistle constantly?

Also got out to hear it better, popped the hood, and it is coming more from underneath than on top... any ideas fellas? need to get this bad boy fixed!!!

jchav62 · 02-08-2008, 01:56 AM

A loose belt maybe? Have you tried tightening the belts?

Kixwy2 · 02-08-2008, 04:08 AM

Something on one of the belts or pulleys?

When I did my engine swap we didn't tighten one of the bolts on the smog pump all the way, and within 10 seconds of startup it worked it's way out to butt up against the pulley. I got a nice whining noise while it buffed the top of the bolt for 20 minutes.

I'd check your assembly from the fan back to make sure some piece of debris didn't get kicked up in there somehow.

chev74 · 02-08-2008, 05:02 AM

not a belt... they're tight. sounds more like its coming from the rear of engine/front of tranny...

dont think its a throwout bearing cuz i know what that sounds like- i think

its a stock 454 with sm465 tranny

GMBowtie79 · 02-08-2008, 08:05 AM

could be the pilot bushing they will tend to do that when they get old.

chev74 · 02-08-2008, 08:54 AM

wont the transmission have to be removed to change this?

GMBowtie79 · 02-08-2008, 09:34 AM

Yes, so depending on how many miles are on the tranny,& clutch, ect. you might want to look into a rebuild. First have it put on a rack or a pit (like at one of those 10min. oil change places) and try to isolate where it is coming from. Could be the pilot, throw out, Or input shaft bearings. Also chech if the tranny is low on gear oil.

chev74 · 02-08-2008, 02:09 PM

wish i had a rack to put it on.... ill have to investigate further and get back with you guys

02-08-2008, 01:19 AM	#1
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	whistling sound... HELP Took about a 150 mile trip the other day and got to a stoplight and started to hear a whistling/chirping sound. My first instinct was a vacuum line, but then i realized that it was increasing with rpm, so wouldnt a vacuum line whistle constantly? Also got out to hear it better, popped the hood, and it is coming more from underneath than on top... any ideas fellas? need to get this bad boy fixed!!!

02-08-2008, 01:56 AM	#2
jchav62 1962 C-10 Join Date: Apr 2005 Location: Las Vegas, New Mexico Posts: 4,978	Re: whistling sound... HELP A loose belt maybe? Have you tried tightening the belts? __________________ Joseph Chavez "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4

02-08-2008, 04:08 AM	#3
Kixwy2 Registered User Join Date: Dec 2007 Location: Central Coast, CA Posts: 177	Re: whistling sound... HELP Something on one of the belts or pulleys? When I did my engine swap we didn't tighten one of the bolts on the smog pump all the way, and within 10 seconds of startup it worked it's way out to butt up against the pulley. I got a nice whining noise while it buffed the top of the bolt for 20 minutes. I'd check your assembly from the fan back to make sure some piece of debris didn't get kicked up in there somehow. __________________ 1974 GMC C-10; my new addiction 1998 4 Runner; daily driver

02-08-2008, 05:02 AM	#4
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	Re: whistling sound... HELP not a belt... they're tight. sounds more like its coming from the rear of engine/front of tranny... dont think its a throwout bearing cuz i know what that sounds like- i think its a stock 454 with sm465 tranny

02-08-2008, 08:05 AM	#5
GMBowtie79 Surviving, one day at a time! Join Date: Jan 2008 Location: Turlock,CA Posts: 295	Re: whistling sound... HELP could be the pilot bushing they will tend to do that when they get old.

02-08-2008, 08:54 AM	#6
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	Re: whistling sound... HELP wont the transmission have to be removed to change this?

02-08-2008, 09:34 AM	#7
GMBowtie79 Surviving, one day at a time! Join Date: Jan 2008 Location: Turlock,CA Posts: 295	Re: whistling sound... HELP Yes, so depending on how many miles are on the tranny,& clutch, ect. you might want to look into a rebuild. First have it put on a rack or a pit (like at one of those 10min. oil change places) and try to isolate where it is coming from. Could be the pilot, throw out, Or input shaft bearings. Also chech if the tranny is low on gear oil. Last edited by GMBowtie79; 02-08-2008 at 09:38 AM.

02-08-2008, 02:09 PM	#8
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	Re: whistling sound... HELP wish i had a rack to put it on.... ill have to investigate further and get back with you guys



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