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Old 06-23-2008, 07:18 PM   #1
crawdad
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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.
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Old 06-23-2008, 08:03 PM   #2
D-Day
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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.
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Old 06-23-2008, 08:18 PM   #3
C-10volvo
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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.
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Old 06-23-2008, 08:56 PM   #4
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Re: Vibration while truck is parked and idling

also check your balancer
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Old 06-23-2008, 10:05 PM   #5
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Re: Vibration while truck is parked and idling

umm tranny mounts...???
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Old 06-23-2008, 10:19 PM   #6
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Re: Vibration while truck is parked and idling

Motor mounts.
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Old 06-24-2008, 12:11 AM   #7
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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....
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Old 06-24-2008, 07:55 AM   #8
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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
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Old 06-24-2008, 09:26 PM   #9
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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....
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Old 06-24-2008, 11:04 PM   #10
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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.
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Old 06-28-2008, 12:06 AM   #11
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Re: Vibration while truck is parked and idling

so what did you find ????
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