knocking sound from rear of engine - The 1947 - Present Chevrolet & GMC Truck Message Board Network

brad20653 · 07-31-2003, 06:57 PM

I put a listening device and its seems to be coming from the flywheel area should that do that ? is it easy to fix ?

mooneyes · 07-31-2003, 07:19 PM

....could be a loose
or cracked

**Stocker** · 07-31-2003, 07:30 PM

If it's auto trans, could be a cracked flex plate. Can be a bit of work, especially if it's 4x4.

Steven Sellers · 07-31-2003, 07:45 PM

If its a standard could be throwout bearing

71GMC_3/4T · 07-31-2003, 07:55 PM

If it's auto, check the torque converter bolts. I've heard of quite a few people who've bought "ruined" vehicles and "fixed" them by tightening the bolts on the torque converter. Sounds like a rod knock.

Longhorn Man · 07-31-2003, 08:21 PM

My old blue longhorn did that to me. The verter bolts backed out just a little. Scared the livin crap outa me when i fired it up, I thought I had some seriouse rod knock going on.

brad20653 · 07-31-2003, 08:33 PM

SEEMS TO GET QUITE after warming

Longhorn Man · 07-31-2003, 08:40 PM

now THAT makes me scared.

*Phillip Johnson* · 07-31-2003, 08:47 PM

Have you checked the oil lately??

brad20653 · 07-31-2003, 08:54 PM

full only got 500 miles on new engine but coming right from flywheel cover and if i reb up it doesnt get loader just same sound

my new 72 · 07-31-2003, 09:14 PM

Maybe the tranny? I think I'll wait untill you get it figured out before I decied to buy or not.

brad20653 · 07-31-2003, 09:18 PM

I started up today and was doing it would tranny do that ? Also somethings kinda hitting the floor board

ABHaulR · 07-31-2003, 09:21 PM

Could be a piston skirt slapping or the wrong thrust bearing on the crank causing the crank to walk back and forth. you can check the crank play from in side the engine comp.

brad20653 · 07-31-2003, 09:23 PM

how ?

Longhorn Man · 07-31-2003, 09:29 PM

Grab the bottom pully and pull on it, then push.
I actually had an engine that I could pull on the crank and get almost 7/16 inch slop back and forth.
It didn't last much longer.

brad20653 · 07-31-2003, 09:30 PM

k if it moves what do i do ?

my new 72 · 07-31-2003, 09:45 PM

If it's a crate, take it back under warranty, if someone built it locally take it to them. if you did it, yank it and replace the thrust bearing.

brad20653 · 08-03-2003, 11:48 AM

Ended up being when i had headers put on the exhaust is hitting the frame

Class of 69 · 08-03-2003, 11:54 AM

Your post about something hitting the floor made me think of motor, or trans mount, but headers is just as easy to fix!!! Glad you came out on the good side this time!

PanelDeland · 08-03-2003, 07:18 PM

You got lucky.I once had a starter nose break off and it rattled in the cover.I thought I was going to be afoot for a while but I got lucky too.

07-31-2003, 06:57 PM	#1
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	knocking sound from rear of engine I put a listening device and its seems to be coming from the flywheel area should that do that ? is it easy to fix ?

07-31-2003, 07:19 PM	#2
mooneyes Registered User Join Date: Jan 2002 Location: Slippery Rock PA USA Posts: 1,692	....could be a loose or cracked __________________ Ken Lyons, Slippery rock pa 68 short step 327 t10 4 gear 72 2wd blazer project 70 lwb 305/700r driver 78 caprice project 02 cavalier D.D ( hate it!!)

07-31-2003, 07:30 PM	#3
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,586	If it's auto trans, could be a cracked flex plate. Can be a bit of work, especially if it's 4x4. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

07-31-2003, 07:45 PM	#4
Steven Sellers Registered User Join Date: Jan 2002 Location: North Carolina Posts: 692	If its a standard could be throwout bearing __________________ 2008 Buick Enclave(wifes new non wrecked) 1996 Jeep Cherokee 2002 2500HD 6.0L (traded) 1998 Jeep Grand Cherokee(wifes/wrecked) 1977 DJ5 postal jeep(mmm lots of fun) 1988 Toyota 2wd p/u(DD, blewup 199,000) 1991 Toyota 2ed p/u (sry just cant break these things) 1997 XR70 Honda 1991 Z50(FOR SALE) 1972 Z50 Honda 1970 SWB 350/knucklebuster "The adventure begins and I am confident that there will be no end".

07-31-2003, 07:55 PM	#5
71GMC_3/4T Weapons Of Construction Join Date: Apr 2000 Location: Colorado, USA Posts: 1,095	If it's auto, check the torque converter bolts. I've heard of quite a few people who've bought "ruined" vehicles and "fixed" them by tightening the bolts on the torque converter. Sounds like a rod knock. __________________ 1971 GMC 2500, 402/TH400 4.10 Daily Driver Lafayette, CO

07-31-2003, 08:21 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	My old blue longhorn did that to me. The verter bolts backed out just a little. Scared the livin crap outa me when i fired it up, I thought I had some seriouse rod knock going on.

07-31-2003, 08:33 PM	#7
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	SEEMS TO GET QUITE after warming

07-31-2003, 08:40 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	now THAT makes me scared.

07-31-2003, 08:47 PM	#9
Phillip Johnson Account Suspended Join Date: Apr 2000 Location: Grants Pass, Oregon Posts: 1,580	Have you checked the oil lately??

07-31-2003, 08:54 PM	#10
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	full only got 500 miles on new engine but coming right from flywheel cover and if i reb up it doesnt get loader just same sound

07-31-2003, 09:14 PM	#11
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	Maybe the tranny? I think I'll wait untill you get it figured out before I decied to buy or not. __________________ I'm going to Law School, wanna debate? It's good practice.

07-31-2003, 09:18 PM	#12
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	I started up today and was doing it would tranny do that ? Also somethings kinda hitting the floor board

07-31-2003, 09:21 PM	#13
ABHaulR Registered User Join Date: Jun 2003 Location: West Valley City, Ut Posts: 311	Could be a piston skirt slapping or the wrong thrust bearing on the crank causing the crank to walk back and forth. you can check the crank play from in side the engine comp. __________________ 72' GMC Suburban 10 1/2" of Lift, 40" Tires! Waiting for restoration 67' Chevy, What to do??? And Bad Ass American Bulldogs!

07-31-2003, 09:23 PM	#14
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	how ?

07-31-2003, 09:29 PM	#15
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Grab the bottom pully and pull on it, then push. I actually had an engine that I could pull on the crank and get almost 7/16 inch slop back and forth. It didn't last much longer.



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07-31-2003, 09:30 PM	#16
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	k if it moves what do i do ?

07-31-2003, 09:45 PM	#17
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	If it's a crate, take it back under warranty, if someone built it locally take it to them. if you did it, yank it and replace the thrust bearing. __________________ I'm going to Law School, wanna debate? It's good practice.

08-03-2003, 11:48 AM	#18
brad20653 Senior Member Join Date: Jul 2003 Location: So. MD Posts: 218	Ended up being when i had headers put on the exhaust is hitting the frame __________________ Soon to have 68 SWB 350 with Turbo350

08-03-2003, 11:54 AM	#19
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	Your post about something hitting the floor made me think of motor, or trans mount, but headers is just as easy to fix!!! Glad you came out on the good side this time! __________________ 69 GMC K10 ..some restoration required....still..

08-03-2003, 07:18 PM	#20
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	You got lucky.I once had a starter nose break off and it rattled in the cover.I thought I was going to be afoot for a while but I got lucky too. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

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