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-   -   Vibration under acceleration (http://forum.e46fanatics.com/showthread.php?t=931547)

grubby_baker 07-05-2012 07:45 PM

Vibration under acceleration
 
I'm at a loss to the point that I finally signed up for the forum. Sorry for this, since I know its been discussed to death, but I am not coming up with specific symptom and a solution to what I have.

Car is a 2005 325xi auto w/ 127k miles.
So, have a vibration under accelration, especially when you get on it. If you don't and baby it, its not very noticeable. It occurs in 2nd and 3rd gear around the 2000 rpm mark. Only under load/acceleration, not while at highway or neighborhood speed. Auto transmission that I recently changed the fluid and filter. Vibration was there before. Recently rebuilt the VANOS, too. I have already replaced the front driver side axle since the boot was cracked, likely contaiminated, and 99% of the forums say this is the culprit.

After replaceing the axle and both control arms, new inner ball joints, and control arm bushings, I'm still having the issue. Didn't replace the the passenger side since it looked fine; no grease loss or cracks or radial movement, just axial as its suppose to.

I visually checked and pulled around the rear axles to see if they were alright the last time I was under the rear of the car. But I can check again.

Thoughts? Transmission? Driveshaft? Rear axles? Am I missing something?

E RaK 07-05-2012 11:10 PM

Try looking into the passenger's side axle again, you never know. Others to consider: TC fluid or front and rear diff oil.

It sounds almost like the car has a turbo that is starting to go. :D Used and abused turbo Subaru's do exactly that. [/USELESS]

grubby_baker 07-06-2012 07:26 AM

I did change the transfer case oil but didn't have a 14mm allen socket to change the diffs. I'll do that since I wanted to anyways, but diffs don't usually shudder under straight line acceleration. We'll see.

I'll also go over the passenger axle with a 'fine tooth comb' and check our dealer records. I do remember them fixing the boot or axle on one of the sides while under warranty. Maybe they didn't get it completely cleaned?

The driver side was a b!%@# to change and I'm not looking forward to the passenger side....

SamDoe1 07-06-2012 10:59 AM

Is it a very short vibration only at 2k rpm?

grubby_baker 07-06-2012 12:17 PM

Pretty short. I drove it today and its actually more around 2400-2700 RPM. Most noticeable in 2nd and 3rd gear. We also really noticed it last weekend when we took a sweeping right from a stop sign and went up a good grade of a street. So its very dependant on load. I decided to go ahead and remove the the passenger axle and swap it with a reman like the driver side since I have the part on hand. I'll keep you all posted on if it goes away...

grubby_baker 07-06-2012 03:21 PM

Just took the car for a test drive. Still does it :( Definetly stops right around 2900 RPM, so I'm almost thinking its the torque converter lockup. I'm going to go get a 14mm hex tomorrow and change the diff fluids and check the rear again, but I don't think its that. I'll also check the driveshaft, but that's usually pretty constant in my experience.

Any new thoughts?

Bobby330xi 07-06-2012 07:17 PM

Check your tires, wheels and balance. I know it sounds trivial, but it makes a huge difference on cars like ours. I have worked on some older VW's that were so critical that the steering wheel would shimmy at 45mph unless the alignment, etc was 100% perfect.

The problem you describe also sounds like a bad rear axle. The part where you say "noticed it last weekend when we took a sweeping right from a stop sign and went up a good grade of a street". I experience the exact same problem if I accelerate HARD while going up a corkscrew type turn. Where I live is very windy country roads with 2,000 foot elevation changes......It really puts the car through its paces and will do a very bad/violent shake/wobble from the rear end if I really get on it under the right conditions. It is so minute that I haven't gotten around to rebuilding/replacing the axles. I was able solve a more minor but constant vibration by repacking the front axles, changing all fluids and having new tires installed (balance and alignment too).

grubby_baker 07-15-2012 12:17 PM

well, removed the exhaust and was able to inspect the driveshaft. The u joints near the slip joint and carrier bearing are loose/sloppy. And the carrier bearing is now wore out. So, sent an email to Driveline Services of Portland for a quote. Broke the studs on the exaust manifold to pipe flange removing the exhaust. Any suggestions on that? Heat and hammer? Drill?

Kubica 07-15-2012 08:38 PM

^try and crack the nuts in half.

Replace motor mount and TC mount if they haven't been done.

cool breeze 07-16-2012 12:30 AM

have the same exact issue currently...

bmwTuner1 07-16-2012 01:23 AM

I dont have an xi but I did have a similar problem. It occurred under load while accelerating and turned out to be the driveshaft CV joint. Worth a check. I spent a pretty penny trying to figure it out and ended up changing every bushing in the car :banghead:

DenverSooner 07-16-2012 10:20 PM

I had the same problem with mine, turned out the MAF needed cleaning. May be too simple for your issue, but it's the simple things on these cars that cause the most problems sometimes

Adamo99 07-16-2012 11:03 PM

Mine did the exact same thing, 6spd, so not a torque converter issue. Try MAF, then coils and/or plugs.

grubby_baker 07-31-2012 07:46 PM

Got the new driveshaft installed. Vibration is all but gone. There is a slight vibe under very hard acceleration. I found that the output shaft of the transfer case to the front driveshaft is a bit sloppy. May be the source. But I'm happy with it for now. For the exhaust studs, I ended up cutting off the studs flush to the flange, center punched them, drilled them out to 5/16" and used stainless cap screws (allen head), 2" long. Looks decent and no exhaust leaks with new gaskets.

winston330xi 08-01-2012 12:19 AM

Why did you replace the whole driveshaft and not just the u joint and center bearing? Was it damaged and unbalanced?

latitude39 08-01-2012 10:18 AM

Quote:

Originally Posted by grubby_baker (Post 14617598)
Got the new driveshaft installed. Vibration is all but gone. There is a slight vibe under very hard acceleration. I found that the output shaft of the transfer case to the front driveshaft is a bit sloppy. May be the source. ...

Do you mean that you feel some play in the transfer case when you rock the front shaft? I think that is normal. My xi also has some play but I don't think that is a problem. Worn u-joints in that shaft would be a problem.

Did you replace the flex disk with the rear drive shaft?

Bentley, p. 260-7, "Rear driveshaft, installing," has very specific instructions for aligning and preloading. ...just an idea.

grubby_baker 08-02-2012 07:41 PM

Quote:

Why did you replace the whole driveshaft and not just the u joint and center bearing? Was it damaged and unbalanced?
The ujoints aren't rebuildable so your only options are to buy a brand new shaft, buy a used one, or buy a rebuilt one. I went the rebuilt route since it comes with a new carrier bearing. I guess if you have your own machine shop and way to balance....could do it yourself.


Quote:

Do you mean that you feel some play in the transfer case when you rock the front shaft? I think that is normal. My xi also has some play but I don't think that is a problem. Worn u-joints in that shaft would be a problem.
No, I agree there is slop in the transfer case as you rotate it and I expect that to be normal. But mine if you move the output shaft up or down/ side to side perpendicular to its axis, it moves like the bearing in the transfer case is wore. U joints on the front drive shaft are good.

I did not replace the guibo as it appeared fine; no tearing, cracks, flaking, etc. Could be it I guess, but its another $125... I did 'preload' teh carrier bearing by pushing it toward the rear of the car as it shows in picture in the Bentley, even though it says in the text 'push toward the front'.

winston330xi 08-03-2012 08:24 AM

Thanks for the info!

cool breeze 08-23-2012 12:34 AM

Quote:

Originally Posted by Kubica (Post 14573497)
^try and crack the nuts in half.

Replace motor mount and TC mount if they haven't been done.

Do you mean the transmission mount? I cant seem to find anyone selling a transfer case mount...thanks

SamDoe1 08-23-2012 09:16 AM

Quote:

Originally Posted by cool breeze (Post 14673328)
Do you mean the transmission mount? I cant seem to find anyone selling a transfer case mount...thanks

^ Yes. Xi doesn't have transmission mounts. The tranny is held up on one side by the engine and the other by the transfer case. This is Xi specific so make sure you get the right one.

Here you go. Item #2:
http://realoem.com/bmw/showparts.do?...59&hg=22&fg=10


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