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Old 12-16-2008, 05:14 PM   #1
time2shine
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need help with a vibration........

What's up guys, I need some help trying to figure out a driveline vibration issue that's driving me nuts. Maybe its something common that i missed in my searches....

I have a bad vibration under acceleration/torque. The higher the rpm, the worse it gets. And it's even worse if/when i'm turning. I put the car on the lift to take a look and i don't see any visual problem. I put a jack on the oil pan and the motor mounts seem nice and stiff. The trans mount however feels pretty soft, but it is not torn. The rear diff also seems to be pretty stiff, but i'm not so sure im testing it the right way.

I have a few questions. Is the trans mount supposed to very soft? would that cause a vibration that gets worse if the car is turning? and how do I figure out if the diff mount(s) are shot.

Another, possibly related issue i have is driveline/driveshaft noise at low speed. It "clunks" in first gear and reverse when i disengage/engage the clutch. I've had that noise from the day i got the car though, when i didnt have the vibration under accell issue.

I understand that it's hard to diagnose a car on a forum, lol. But any tips, suggestions or help is greatly appreciated. The car is out of warranty by time....
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Old 12-16-2008, 06:27 PM   #2
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Quote:
Originally Posted by time2shine...View Post
Another, possibly related issue i have is driveline/driveshaft noise at low speed. It "clunks" in first gear and reverse when i disengage/engage the clutch. I've had that noise from the day i got the car though, when i didnt have the vibration under accell issue.

I understand that it's hard to diagnose a car on a forum, lol. But any tips, suggestions or help is greatly appreciated. The car is out of warranty by time....

I don't know about the first part but I get that clunk too, usually only at low RPM. If I let it rev on through to around 3k, I don't hear it. I was doing some reading on here last night and found a couple threads about it. From what I can gather it's normal, and just a function of driveline slack, and things having torque on them that suddenly lets off, and then back on. No idea why it happens at low rpm and not higher ones, but apparently that's just how it is.
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Old 12-16-2008, 06:53 PM   #3
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Have you done any drive shaft mods?
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Old 12-16-2008, 07:27 PM   #4
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Quote:
Originally Posted by jaqattack02...View Post
I don't know about the first part but I get that clunk too, usually only at low RPM. If I let it rev on through to around 3k, I don't hear it. I was doing some reading on here last night and found a couple threads about it. From what I can gather it's normal, and just a function of driveline slack, and things having torque on them that suddenly lets off, and then back on. No idea why it happens at low rpm and not higher ones, but apparently that's just how it is.

yes, i have heard other people mention it also. Driveshaft slack is exactly what it sounds like, juts a little excessive though lol. It most likely has nothing to do with the vibration i'm feeling under torque and steering. thanks.

Quote:
Originally Posted by Gforce1320...View Post
Have you done any drive shaft mods?

no mods at all. If i take off very gently, you don't even notice. but if i take off gently while turning, then it's just as noticeable as if i was accellerating hard. I'm leaning towards trans mount because i can feel the shifter vibrate more than anything and the source of the vibration seems to be coming from the bellhousing area. But like i said, the mount visualy looks good.
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Old 12-16-2008, 08:09 PM   #5
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I had very similar symptoms involving a two piece driveshaft with U-Joints vice the rubber joints we had. The clunk sounded just like the U-Joint being bad. On Closer inspection we found driveshaft bolts to the pinion adapter were loose. In your case that might be the bolts from the DS to the pinion. Sometimes that isn't visually obvious.

Another time I found the nuts that bolt the differential to the body to be a cuplrit, three were finger loose.

I have also heard of the bolts on the stubs and hubs working loose, it was not an uncommon problem with the 04s.

Check them all. It is a cinch the hard shifting results from compression of the drivetrain pulling something out of whack. Do you notice your shifter handle moving with the tranny assembly when you are under torque?
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Old 12-17-2008, 07:25 AM   #6
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i will check all the bolts as soon as I get a chance to put it on a lift. But this has been going on for a good month now. I don't drive it much right now cause it's winter. We just got some snow yesterday so I won't move the car untill the roads are cleared and some rain washes off the salt. thanks for your help.
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Old 12-17-2008, 08:09 AM   #7
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Originally Posted by time2shine...View Post
i will check all the bolts as soon as I get a chance to put it on a lift. But this has been going on for a good month now. I don't drive it much right now cause it's winter. We just got some snow yesterday so I won't move the car untill the roads are cleared and some rain washes off the salt. thanks for your help.

Mine went on at least that long. Jack the dang thing up and put it on jackstands and crawl under it...feel the pain The lord made hot rods for us to bust our knuckles on when the weather was freezing. He made snow to cushion our backs and freeze our asses laying under the hot rods. He even designed dinosaurs to live die and ferment into wine to drip in our faces and mingle with the blood on our hands after working around GTO heat shielding. JMHO sorry for the rant

Last edited by wrp; 12-17-2008 at 08:11 AM.
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Old 12-17-2008, 08:44 AM   #8
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Originally Posted by wrp...View Post
Mine went on at least that long. Jack the dang thing up and put it on jackstands and crawl under it...feel the pain The lord made hot rods for us to bust our knuckles on when the weather was freezing. He made snow to cushion our backs and freeze our asses laying under the hot rods. He even designed dinosaurs to live die and ferment into wine to drip in our faces and mingle with the blood on our hands after working around GTO heat shielding. JMHO sorry for the rant

This quote should be a sticky!
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Old 12-17-2008, 04:32 PM   #9
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Originally Posted by wrp...View Post
Mine went on at least that long. Jack the dang thing up and put it on jackstands and crawl under it...feel the pain The lord made hot rods for us to bust our knuckles on when the weather was freezing. He made snow to cushion our backs and freeze our asses laying under the hot rods. He even designed dinosaurs to live die and ferment into wine to drip in our faces and mingle with the blood on our hands after working around GTO heat shielding. JMHO sorry for the rant



that was good
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Old 12-17-2008, 07:57 PM   #10
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also check that the ds bolts are not bent
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Old 05-13-2009, 07:02 PM   #11
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update:

I finally got around to putting the car on the lift and checking all the bolts on the driveshaft and rear end. Everything is tight. The donut in the middle of the driveshaft seem nice and firm too. The tranny mount seems a little soft, but i'm just not conviced that's the problem. And the vibration seems to have gotten worse. I feel it all the time now, the power is just not smooth. Like something is out of balance.
I remember when I first got the car,it had 11k miles on it. I'd feel it over 5k rpm when accelerating hard. I remember even thinking that's kinda weird considering the car was so smooth up until i hit over 5k. But since it only happened at such high rpm and i didn't drive like that most of the time, i didn't care about it. Last year I started noticing a little more frequently, mostly if i was accelerating on a turn, with the weight shifted one way. But now it seems to be there all the time. Like i said, the power doesn't feel smooth, not a violent vibration, more of a high frequency buzzing feeling. And the shifter seem to shake more at higher rpms. I'm currently at 30k miles.
I'm getting frustrated with it. I want to do some suspension mods, but I really want this taken care of first. I miss the smooth BMW like acceleration

Please help....
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Old 05-13-2009, 07:07 PM   #12
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Quote:
Originally Posted by Non-Sponsor-Engineering...View Post
also check that the ds bolts are not bent

I didn't check for that, I guess it's possible. Let me know if that's something I should still look into after reading my latest post. Thanks

BTW, I've NEVER beaten the car up. I don't think I've ever redlined or power shifted and I'm pretty sure I have 2 mild burnouts on my record since getting the car. The guy before me was also a big car nut and took great care of it, it was like a brand new car, but he told me he raced it a couple of times.

One final note, I have difficulty shifting into 2nd sometimes and it almost always grinds 2nd on a hard launch. I'm pretty sure it's the b&m shifter, but at this point i'm not ruling out anything.
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Old 05-14-2009, 09:25 AM   #13
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bump
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Old 05-15-2009, 05:06 PM   #14
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weekend bumpage
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Old 10-03-2010, 05:30 PM   #15
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Sorry for digging up old threads, but did you ever figure this out.

I've noticed for a couple weeks that I get a little drive train vibration if I go WOT around 3k. Seems very prevalent in 3rd gear. It's not there if I'm coasting or just cruising around. Almost feels like a wheel vibration problem but it goes away as soon as I'm off the throttle.

Any ideas?
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