WTF? my rear end is ringing? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Suicide-D · 09-26-2002, 11:08 AM

I have an interesting developement in my 68. I heard a periodic bell sound when the truck was not under a load... I didn't have my foot on the gas or on the brake. It sounds like something flopping around and hitting something. to accurately describe it ... it sounds like someone sticking their finger in a fan. I think it does change with rpm I havent caught that yet... it is definately behind me. Well as of this weekend it now does it every time I let my foot off the accelerator, it used to stop when I hit the brake but I still hear it now and it will fade with the brakes applied. Where should I start my investigation? I made sure there wasn't anything obvious like something wrapped around the drive shaft or a broken shock bouncing around... everything looks normal.

Thanks,
Perplexed

adamls · 09-26-2002, 11:19 AM

Man noises are hard to pinpoint, unless the noise leads to breakage. I chased a noise in 99 Sierra for a year and found it to be a piece of tape slapping the hood. I would start with the brakes then go to the rear end and the, god forbid, the tranny. Put the rear up on jack stands, let someone else run it while you listen.

jostrans68 · 09-26-2002, 12:55 PM

When my 68 made a noise like that it was the carrier bearing coming apart a week later it was toasted.............

Suicide-D · 09-26-2002, 12:58 PM

well I don't have a carrier bearing.. one piece driveshaft...

**ThreeQuarter** · 09-26-2002, 01:04 PM

Check you u-joints. I've had bad u-joints cause a ringing sound when I put it into gear (auto). Ka-chiiiing! I've also driven a newly-bought truck for a couple thousand miles before I realized the rearmost u-joint had no more bearings left, just worn, rusty nubs clanking around in a beat-up cup. Yes, I am a lucky man. I had dismissed it as slack in the rear end. Good luck!

bigjimzlll · 09-26-2002, 02:56 PM

if its something in the rear end...dont worry it will find its way out..mine did, a nice dime size hole in the diff. cover. funny thing though, after careful inspection, I couldn't find anything wrong. Now no more noise or clunks or vibration

**1971Stepside** · 09-26-2002, 03:30 PM

Did you sit on your cell phone.....hehehehe I couldn't resist!

meathead95 · 09-26-2002, 03:39 PM

check your pinion nut

Suicide-D · 09-26-2002, 04:03 PM

I get it... ha ha rearend ringing....I will pull the cover and snoop around.:p

OLDCHEV4X4 · 09-26-2002, 10:11 PM

My ring gear bolts came loose one time and made a ringing noise, a clunking noise, and finally a loud bang noise. I looked under my truck and my diff cover had a hole in it the size of a ring gear bolt and oil was running out. I gooped the hole with RTV , filled it back up and drove it home.

I also had the pinion nut come loose on another truck. You gotta use red locktight on them.

And another time a pinion bearing went bad and was ringing on my blazer. It only made noise between 45 and 55 MPH.

Randy

72step · 09-27-2002, 04:51 PM

Dirt Dobber, Keep me posted on what you find, my truck has developed a similar noise. To me it's more of a whine or continiuous ring, than fingers in a fan. Keep me posted. Much appreciated...

Michael A. K. G · 09-27-2002, 04:59 PM

A whine is a different problem.

A speed dependent high pitch whine suggests a failing pinion bearing, though there are other things it could be.

BTW, if the "finger-in-the-fan" noise changes with RPM and not speed, it can't possibly be in the rear end at all. It has to be in the engine or transmission, or be related to a belt-driven accessory.

09-26-2002, 11:08 AM	#1
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	WTF? my rear end is ringing? I have an interesting developement in my 68. I heard a periodic bell sound when the truck was not under a load... I didn't have my foot on the gas or on the brake. It sounds like something flopping around and hitting something. to accurately describe it ... it sounds like someone sticking their finger in a fan. I think it does change with rpm I havent caught that yet... it is definately behind me. Well as of this weekend it now does it every time I let my foot off the accelerator, it used to stop when I hit the brake but I still hear it now and it will fade with the brakes applied. Where should I start my investigation? I made sure there wasn't anything obvious like something wrapped around the drive shaft or a broken shock bouncing around... everything looks normal. Thanks, Perplexed

09-26-2002, 11:19 AM	#2
adamls Gotta Startem Early Join Date: Oct 2001 Location: Amarillo, TX, USA Posts: 364	Man noises are hard to pinpoint, unless the noise leads to breakage. I chased a noise in 99 Sierra for a year and found it to be a piece of tape slapping the hood. I would start with the brakes then go to the rear end and the, god forbid, the tranny. Put the rear up on jack stands, let someone else run it while you listen. __________________ 67 SWB In Progress, one piece at a time, maybe 3 years I will be finished

09-26-2002, 12:55 PM	#3
jostrans68 Jostrans68 Join Date: Mar 2001 Location: Bloomington indiana Posts: 1,182	When my 68 made a noise like that it was the carrier bearing coming apart a week later it was toasted............. __________________ [CGTW Member former 67-72 now with a 96 silverado

09-26-2002, 01:04 PM	#5
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,522	Check you u-joints. I've had bad u-joints cause a ringing sound when I put it into gear (auto). Ka-chiiiing! I've also driven a newly-bought truck for a couple thousand miles before I realized the rearmost u-joint had no more bearings left, just worn, rusty nubs clanking around in a beat-up cup. Yes, I am a lucky man. I had dismissed it as slack in the rear end. Good luck! __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3

09-26-2002, 02:56 PM	#6
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	if its something in the rear end...dont worry it will find its way out..mine did, a nice dime size hole in the diff. cover. funny thing though, after careful inspection, I couldn't find anything wrong. Now no more noise or clunks or vibration __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

09-26-2002, 12:58 PM	#4
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	well I don't have a carrier bearing.. one piece driveshaft...

09-26-2002, 03:30 PM	#7
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	Did you sit on your cell phone.....hehehehe I couldn't resist! __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

09-26-2002, 03:39 PM	#8
meathead95 computer illiterate Join Date: Jan 2001 Location: Des Moines, IA Posts: 6,446	check your pinion nut __________________ 72 2wd blazer 72 swb 4x4

09-26-2002, 04:03 PM	#9
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	I get it... ha ha rearend ringing....I will pull the cover and snoop around.:p

09-26-2002, 10:11 PM	#10
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	My ring gear bolts came loose one time and made a ringing noise, a clunking noise, and finally a loud bang noise. I looked under my truck and my diff cover had a hole in it the size of a ring gear bolt and oil was running out. I gooped the hole with RTV , filled it back up and drove it home. I also had the pinion nut come loose on another truck. You gotta use red locktight on them. And another time a pinion bearing went bad and was ringing on my blazer. It only made noise between 45 and 55 MPH. Randy __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

09-27-2002, 04:51 PM	#11
72step Registered User Join Date: Nov 2000 Location: chimayo, nm, usa Posts: 898	Dirt Dobber Dirt Dobber, Keep me posted on what you find, my truck has developed a similar noise. To me it's more of a whine or continiuous ring, than fingers in a fan. Keep me posted. Much appreciated...

09-27-2002, 04:59 PM	#12
Michael A. K. G Registered User Join Date: Jul 2002 Location: California central coast Posts: 126	A whine is a different problem. A speed dependent high pitch whine suggests a failing pinion bearing, though there are other things it could be. BTW, if the "finger-in-the-fan" noise changes with RPM and not speed, it can't possibly be in the rear end at all. It has to be in the engine or transmission, or be related to a belt-driven accessory.



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