The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 06-23-2008, 07:18 PM   #1
crawdad
Senior Member
 
crawdad's Avatar
 
Join Date: Sep 2004
Location: Georgia
Posts: 614
Vibration while truck is parked and idling

When I crank up my truck and it is on a fast idle (around 1500 RPM or so), I notice a vibration. I can't tell if its coming from the engine or the transmission. It's hard to explain, but I've noticed that it is not a constant vibration, but seems to be rotational related that vibrates through only a portion of the engine or tranny rotation (if that makes sense at all), i.e., on again...off again, etc. If I give it a few hundred more RPM, the vibration disappears. I don't notice it at all when I'm driving. I use to have another chevy truck that did the same thing and I never did find the cause. I'm wondering if it might be the harmonic balancer or maybe the torque converter. Anybody got any ideas what it might be or things that I need to check? Thanks.
__________________

2012 Silverado LT 1500, 5.3, 6 speed auto
'86 SWB C-10 Silverado
crawdad is offline   Reply With Quote
Old 06-23-2008, 08:03 PM   #2
D-Day
Live fast, die young
 
D-Day's Avatar
 
Join Date: Sep 2006
Location: Northwest Ohio
Posts: 293
Re: Vibration while truck is parked and idling

Is the transmission vibrating against the floorboards? My 700R4 is a tight fit, and will do that sometimes on hard acceleration around a turn.
D-Day is offline   Reply With Quote
Old 06-23-2008, 08:18 PM   #3
C-10volvo
Registered User
 
C-10volvo's Avatar
 
Join Date: May 2003
Location: Lake Oswego, Oregon
Posts: 1,028
Re: Vibration while truck is parked and idling

Pull the inspection cover off the tranny and make sure the flywheel bolts are tight. Then start the motor and then look at the flywheel again to make sure it is not bent. If everything checks out it could be something in the motor.
__________________
Ken Morgan
For fun: 1964 Volvo 122
For slow: 1984 Chevrolet C-10
For everything else: 1997 BMW M3
C-10volvo is offline   Reply With Quote
Old 06-23-2008, 08:56 PM   #4
COMP
Registered User
 
Join Date: May 2008
Location: Eville IN.
Posts: 365
Re: Vibration while truck is parked and idling

also check your balancer
COMP is offline   Reply With Quote
Old 06-23-2008, 10:05 PM   #5
dammitmitchell
the pollock
 
dammitmitchell's Avatar
 
Join Date: May 2008
Location: abilene, texas
Posts: 4,423
Re: Vibration while truck is parked and idling

umm tranny mounts...???
__________________
Jack of ALL trades, Master of none.. (but one... procrastination)
Army vet 02-08
RIP El Jay! Miss you brother!


http://67-72chevytrucks.com/vboard/s...d.php?t=343538
http://67-72chevytrucks.com/vboard/s...d.php?t=386042
dammitmitchell is offline   Reply With Quote
Old 06-23-2008, 10:19 PM   #6
spoon
Registered Penetrator
 
spoon's Avatar
 
Join Date: Feb 2008
Location: Salinas, CA
Posts: 153
Re: Vibration while truck is parked and idling

Motor mounts.
__________________
"Some people wear Superman pajamas. Superman wears Chuck Norris pajamas."
"Chuck Norris is the only person on the planet that can kick you in the back of the face."
"Chuck Norris doesn't 'tea-bag'... he 'potato-sacks.'"
spoon is offline   Reply With Quote
Old 06-24-2008, 12:11 AM   #7
lurch115
Registered User
 
lurch115's Avatar
 
Join Date: Oct 2006
Location: iowa
Posts: 722
Re: Vibration while truck is parked and idling

i'd bet on the motor and tranny mounts also....just changed the tranny mount in mine last fall even though it wasn't all that bad and it made a HUGE difference...made it alot quieter in the cab too....
__________________

"Horsepower is how fast you hit the wall, torque is how far you carry the wall with you."
'84 chevy half ton short box 2wd, 67,000 actual miles
'03 chevy 1500 HD crew cab 4x4 standard box, 6.0L
lurch115 is offline   Reply With Quote
Old 06-24-2008, 07:55 AM   #8
James McClure
One shot, one kill.
 
Join Date: Dec 2007
Location: Saratoga Springs NY
Posts: 859
Re: Vibration while truck is parked and idling

Crawdad, To seperate the problem into engine or trans, unbolt the converter and push it back away from the flywheel. Rotate it 360 degrees to make sure it will clear the flywheel. Start the engine and bring it up to vibration RPM and see if it vibrates. Yes, eng related, No, trans related. Check out what was stated above. IF vibration is very light I would change the mounts. Heavy vibrations are usually accompinied with a noise. Noise= trouble, find it and fix it, jim
__________________
1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.
James McClure is offline   Reply With Quote
Old 06-24-2008, 09:26 PM   #9
dammitmitchell
the pollock
 
dammitmitchell's Avatar
 
Join Date: May 2008
Location: abilene, texas
Posts: 4,423
Re: Vibration while truck is parked and idling

ohh heres one i had a loud "clanking" during start up idle... it was a loose exhaust mount! he he he....
__________________
Jack of ALL trades, Master of none.. (but one... procrastination)
Army vet 02-08
RIP El Jay! Miss you brother!


http://67-72chevytrucks.com/vboard/s...d.php?t=343538
http://67-72chevytrucks.com/vboard/s...d.php?t=386042
dammitmitchell is offline   Reply With Quote
Old 06-24-2008, 11:04 PM   #10
westie 666
Registered User
 
westie 666's Avatar
 
Join Date: Mar 2008
Location: AUCKLAND NZ
Posts: 264
Re: Vibration while truck is parked and idling

I had a vibration in a 71 statesman, turned out to be a cracked fan blade it broke off and went through the hood.
__________________
77 Cheyenne no longer in bits
westie 666 is offline   Reply With Quote
Old 06-28-2008, 12:06 AM   #11
COMP
Registered User
 
Join Date: May 2008
Location: Eville IN.
Posts: 365
Re: Vibration while truck is parked and idling

so what did you find ????
COMP is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:20 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com