1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

bad vibrations

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Old Apr 27, 2006 | 10:35 PM
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drift_raptor's Avatar
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From: san diego
Question bad vibrations

Ok so i picked up my 12a last week and for the most part she runs really strong. the only major gripe is that once i hit about 45 mph it starts to vibrate and when i let off the gas it gets worse and when i accelerate it goes away..i think its my lsd which will be replaced soon enough but i wanted to pick some brains of more exp owners.
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Old Apr 28, 2006 | 01:56 AM
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kiwi from downunder..
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From: springfield,oregon
is this in like 4th gear?
have probaly the same thing lots of vibration evan goin 70 i feel the vibration im thinkin maybe tranny or engine mounts

or maybe exsaust myn rattles alot soon will fall off but i can feel that as well
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Old Apr 28, 2006 | 02:13 AM
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From: morganton, NC
it could be a bad wheel bearing.. i dont think it has anything to do with your lsd
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Old Apr 28, 2006 | 02:20 AM
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The most likely cause of a speed-related vibration is a bad driveshaft, plus it's an easy thing to check and deal with if it proves the culprit. You might as well start there.
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Old Apr 28, 2006 | 02:31 AM
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From: chamber of farts
YOU'rE YOKES ARE GOING OUT! DANGER TO U-JOINTS!
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Old Apr 29, 2006 | 05:32 PM
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From: san diego
cool thanks guys ill check those asap and no it starts b4 4th gear
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Old Apr 29, 2006 | 11:03 PM
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If its speed related and goes away as you get faster it could well be a wheel balance issue.
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Old Apr 29, 2006 | 11:05 PM
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From: chamber of farts
Originally Posted by drift_raptor
cool thanks guys ill check those asap and no it starts b4 4th gear
My friend had the same problem but it happened before 5th and hard to shift.
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Old Apr 30, 2006 | 02:22 AM
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kiwi from downunder..
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From: springfield,oregon
so whats involved with checking the drivesharft i dont have a clue

when i turn left,well hard left it makes a clunking noise kinda like a slow cv clunk and disapairs when goin straight i dont think iv heard it turnin right what could this be?

i get vibrations from 3-5gear
and at idel
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Old Apr 30, 2006 | 08:02 AM
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if it was a rear u-joint you would feel it through all gears during acceleration. If it was a front u-joint you would feel it during deceleration. That pretty much eliminates that as the cause since you said it goes away at times. I would agree that it could very well be a wheel balance issue or wheel bearing. The hard left turn clunk would have me concentrating on the left front tire. I recently had my left front wheel bearing nut work it self loose and that caused a slight vibration at higher speeds. Did your 7 sit for a while in the same spot before hitting the road?

jim
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Old Apr 30, 2006 | 08:06 AM
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Originally Posted by blwfly
so whats involved with checking the drivesharft i dont have a clue

when i turn left,well hard left it makes a clunking noise kinda like a slow cv clunk and disapairs when goin straight i dont think iv heard it turnin right what could this be?

i get vibrations from 3-5gear
and at idel
vibrations at idle, check motor mounts.
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Old Apr 30, 2006 | 08:39 AM
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I have a simular vibration issue. At EXACTLY 38 miles an hour I get this low level vibration that you hear more then feal. Super deep sound that almost hurts your ears. If you power through and make it to 40, it goes away.

I think I need to get tires rotated/balanced.
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Old Apr 30, 2006 | 12:50 PM
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kiwi from downunder..
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From: springfield,oregon
Originally Posted by seldawg
if it was a rear u-joint you would feel it through all gears during acceleration. If it was a front u-joint you would feel it during deceleration. That pretty much eliminates that as the cause since you said it goes away at times. I would agree that it could very well be a wheel balance issue or wheel bearing. The hard left turn clunk would have me concentrating on the left front tire. I recently had my left front wheel bearing nut work it self loose and that caused a slight vibration at higher speeds. Did your 7 sit for a while in the same spot before hitting the road?

jim
i get vibrations when deceleration too
can you give me a lil more info on the wheel bearing nut so i know where it is. behind the rotor? hard to replace?

what am i looking for when checking engine mounts i cant move the motor when its turned off its on there solid i cant shake the motor
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Old Apr 30, 2006 | 01:00 PM
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wheel bearing nut is behind the cap that you will see once your remove the tire if you still have stock rims. Jack the front tire up so there is no weight on it. If your wheel bearing is loose at all you will be able to feel play in your tire. Grab the tire and push / pull in and out.( best way I can describe it ). To get to the wheel bearing just remove the cap with a screwdriver and you will see a metal retainer with a cotter pin. If you need to tighten it remove the retainer and pin and tighten it down. NOT all the way though. get it snug and then back it up a smidge.
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