At my wits end with driveshaft vibration

[stargazer_61]

Well, as the title says...

A few months ago, I replaced a shredded center bearing, in similar condition to what Jon K posted, due to knocking in low speeds/gears. Vibration didn't go away, but was reduced. So I replaced collapsed engine & trans mounts, but that didn't do it either. So I babied the car until I could get the time to redo the center bearing & guibo. In the process of babying, I broke another center bearing. Anyway...

Yesterday I finally replaced the guibo & center bearing. Took the driveshaft to the BMW dealer in Chapel Hill to have them look at the U & CV joint. Tech thought they were okay - U was smooth with no notchiness, and no noises in the CV (he called it "tinging"). Got the car back together & took it out to a little used road with twisties. Slight vibe around 20 mph, but no banging at 30-35. Yay! So I really exercised it for the first time in months, sport mode, flooring it, 70mph through 35mph turns, smooooth...

Parked the car for an hour. Left the house to go pick up my daugher at work. At 20mph, I hear knocking. Argh!!! Lots of low speed vibration now. What have I done or forgotten to do?

FYI, the old guibo was pretty mushy. Lots of fractures, but not shredded. New one is rather stiff. I did not preload the bearing. I allowed it to "settle", then tightened it down. I believe that it is installed the correct way, and the driveshaft was marked to properly reassemble it. I did not mark the diff or trans flange to put the driveshaft back in the same holes. Would this make a difference?

[joshua43214]

Marking the flanges should not have been needed, I always do just to be safe, but I am anal about some things. Some people have been posting lately about getting bad OEM guibo's out of the box, seems they are hard as a rock and do ot flex the way they are supposed to, maybe you have one of these?

Can you tell where the noise is coing from? sometmes driving down an alleyway with building crowded on both sides can help locate noises. Try driving with the windows up and the windows down, rear window up/down etc. If it makes noise inside at 20mph, there is a good chance you can hear it at 10mph or so if you are in a narrow alley.

An out of balance drive shaft should not vibrate until higher speed, low speed vibration is a sign of binding. Might be worth double checking the carrier bearing is aligned properly. Also make sure its faceing the right way, the mount can be put on backwards.

[Bellicose Right Winger]

Interesting that you didn't have any problems upon reassembly, but only after the 1 hour "hot soak". I think this rules out the stiffness of guibo being the problem. Exhaust and catalyst heat rises and cooks the drive shaft after a driven car sits, particularly if the heat shield is damaged or missing. I'd try to preload the center bearing, it's the seems to be the only thing that could be improved upon. I doubt it's installed backwards as it's mounting flanges are different lengths and drivesahft would be noticeably offset if it were. Is vibration still present after car has been sitting overnight, letting everything cool off?

Paul Shovestul

[Derek A.]

1. Output shaft bushing in transmission is shot ??
2. Driveshaft itself is out of balance.
3. Maybe you are feeling a number of different things - wheel tire & driveshaft ?

[stargazer_61]

To answer some of your questions:

Right now, it is a thumping. It is definitely coming from the d/s tunnel. It is definitely at low speed.

I am not sure about cool down reducing it. Right now it is up in the air, all four wheels, and the exhaust is off, so I can see what is going on. It feels solid, the carrier bearing did not break (again).

The input shaft bushing was worn, but two stealers did not have the part available. I put it back together anyway.

Wheel & tire balance appear to be good. At speed on smooth roads it feels fine. Was last balanced on a Hunter.

Prior to removing the exhausts, I ran it with the rear wheels off the ground. I can feel the vibration, though at a higher indicated speed, leading me to believe that due to less torque being required to turn the wheels, the vibe requires higher speed to come in.

[joshua43214]

I doubt it's installed backwards as it's mounting flanges are different lengths and drivesahft would be noticeably offset if it were.
Paul Shovestul

This was my point exactly, the offset is not so noticeable when the car is on jacks, and even if its on a lift, it can be overlooked. We had a person recently on the board do exactly this not long ago.

I am also a bit concerned about the carrier bearing breaking after a replacement, did you ever determine the cause the the last bearing failure?

[stargazer_61]

I have no idea why it broke. I suspect it was the guibo, which was quite weak, so I replaced that as well.

Here is an update to what I have since discovered:

The bearing is indeed on with the correct orientation. The d/s is straight. Ran the car up to about 60mph on the jacks, noticeable vibration. Had the wife run it up while I crawled underneath of it. D/s does not vibrate and is not off center - I put my hand on it while it was turning at the trans, both sides of the carrier bearing, and at the diff. Smooth, virtually zero axial deviation.

However, the left rear axle was bouncing quite a bit. I put a floor jack underneath the control arm and raised it up a bit. Vibration was less, but still present. Then I noticed a lump in the tire, on the inside sidewall. Looks like I blew out a belt whilst thrashing it yesterday. Tire is worn in the typical, inside tread location, and the balance has obviously been thrown off.

The conclusion is that my d/s vibration should be cured, but I need new tires for the rear.

Thanks all for the assistance.

[stargazer_61]

Well, the vibration still is not cured. However, I believe that the vibration may be related to the rear end. Occurance is at low speeds, up to 25 mph, then is gone. The noise is a thunking along with the shake. Prior to changing the carrier bearing & guibo, it would vibrate up to 45 mph.

Had a look at my pitman arms. The bushings are completely compressed and practically gone. Also, the rear control arm bushings on the driver side appear to be goners as well. It could be dirt and crud, I will have to clean it up to be sure. Passenger side bushings look okay. Subframes as well look okay, but it is hard to tell without removing the arms that are bolted to them.

The only time I don't get any vibrations in the car is when it is up in the air and the rear tires are off. The bad tire is now in the trunk and the spare is on. Any other suggestions before I take it into the shop?

[632 Regal]

2 piece driveshaft? If you seperated it the axial of the 2 could be off causing binding noticable at lower rpms.

[joshua43214]

My thoughts are that if the vibration goes away when the vehicle is raised, it means something is not positioned properly to run at ride hight.

Since you have had an unexplained carrier bearing failure, and what sounds to me like drive shaft binding now, I would be suspiciouse of the positioning of the carrier bearing or the plunge joint. You did mount the carrier with the car flat on the ground?

[Bill R.]

car on the ground?



My thoughts are that if the vibration goes away when the vehicle is raised, it means something is not positioned properly to run at ride hight.

Since you have had an unexplained carrier bearing failure, and what sounds to me like drive shaft binding now, I would be suspiciouse of the positioning of the carrier bearing or the plunge joint. You did mount the carrier with the car flat on the ground?

[Bill R.]

unsupported? If so that puts the rear cv joints at extreme angles and won't work. If you wish to run the car in the air it has to be well supported and the rear suspension loaded so the axle shaft angles are at the normal angles for the car when driving.




Well, the vibration still is not cured. However, I believe that the vibration may be related to the rear end. Occurance is at low speeds, up to 25 mph, then is gone. The noise is a thunking along with the shake. Prior to changing the carrier bearing & guibo, it would vibrate up to 45 mph.

Had a look at my pitman arms. The bushings are completely compressed and practically gone. Also, the rear control arm bushings on the driver side appear to be goners as well. It could be dirt and crud, I will have to clean it up to be sure. Passenger side bushings look okay. Subframes as well look okay, but it is hard to tell without removing the arms that are bolted to them.

The only time I don't get any vibrations in the car is when it is up in the air and the rear tires are off. The bad tire is now in the trunk and the spare is on. Any other suggestions before I take it into the shop?

[stargazer_61]

No, I mounted it with the front end up on ramps. Installed in this sequence:

1) D/S to Differential
2) D/S to Transmission
3) Carrier Bearing to Frame

I wanted to make sure that there was no excess weight on the bearing, plus I wanted to let it "settle" so that it was perpendicular to the D/S.

What is the "plunge joint"

Jeff, the axial you are referring to, would that be the axial at the D/S splines where it goes back together?

[stargazer_61]

unsupported? If so that puts the rear cv joints at extreme angles and won't work. If you wish to run the car in the air it has to be well supported and the rear suspension loaded so the axle shaft angles are at the normal angles for the car when driving.

Okay. That makes a lot of sense. Next time it is up in the air, I will definitely load the rear suspension with my floor jacks after it is properly supported on the jack stands.

The vibration was still there, up to 25 mph, after the car was put back together and test driven.

[joshua43214]

Plunge joint is part number 13

http://www.realoem.com/bmw/showparts.do?model=HE63&mospid=47410&btnr=26_0094&hg=26&fg=10

[Derek A.]

Do you have a rear caliper that is hung up? Maybe has warped a rotor and that is what you are feeling ?

[632 Regal]

yes, if the phasing is off it can bind a bit. I dont know why it will but thats what the books say and if you hold it in your hands it binds...havent figured why in my head yet, just know it does.


would that be the axial at the D/S splines where it goes back together?

[stargazer_61]

Joshua, the BMW tech didn't think there was anything wrong with that joint. He said it would be noisy if there were an issue with it. But as it was not on the car when he checked it, he admitted that he could not be sure.

Derek, my rotors and calipers are in good shape as far as I can tell, but I will check them for warpage anyway. Wheel spins pretty freely upon release of the brakes.

Jeff, I will check my book on that phasing with the assembly joint. I am with you in that I cannot quite see why in my head.

[mattyb]

I was under ther impression that the centre bearing required preload when tightening and fitting. also agree with the spline alignement theory

[stargazer_61]

I was under ther impression that the centre bearing required preload when tightening and fitting. also agree with the spline alignement theory

Okay. I can pretty easily get back under there and preload the bearing. I was just afraid that I would mis-align it. It gets easier to drop the exhaust every time I go underneath...

I don't quite understand this spline alignment theory, though. Is it because there is wiggle room, however slight, causing the shaft to not be absolutely straight at that joint? I would think that when tightening the bolt, that the two halves would be pressed together properly. Or is it that it is minutely turned, with the splines not precisely centered?

[mattyb]

when the shaft is balanced it is done so in one piece. with how ever many splines on the shaft, i dont know, didnt count them, and balancing weighted to the miligram the shaft being one spline out means that it is 1-2mm out of whack. at speed this becomes evident. I am not a sceintist or a mechanic but im sure you get the drift.

technical definitions Glossary:

Whack: a non denominational term to desribe a measure of mechanical distance or relativity that is undefinalbe yet understood globally as a unit of measure or level of fuk up.

[genphreak]

Okay. I can pretty easily get back under there and preload the bearing. I was just afraid that I would mis-align it. It gets easier to drop the exhaust every time I go underneath...

I don't quite understand this spline alignment theory, though. Is it because there is wiggle room, however slight, causing the shaft to not be absolutely straight at that joint? I would think that when tightening the bolt, that the two halves would be pressed together properly. Or is it that it is minutely turned, with the splines not precisely centered?I reckon your centre bearing could be blown again. they are weak as piss, so any trouble down the back breaks them at the joint where their pissy outer carrier welds to their pissy little bracket. They really aren't designed to take load. If they do something else is wrong. No matter what after you isolate the root cause, you might find the centre bearing's mounting is fatigued or damaged.

I'll go out on a limb here with a little theory; (from the last failiure in mine) Bad dogbones ie pitman arms can blow the centre bearing when a lot of power is applied and excessive oversteer induced.

As the car slides, should the driver try to regain accelerational control without backing off the throttle straight away, severe and prolonged jagged stresses are induced in the driveline as the tyres continue to fight for traction as the driveline prevents solid grip due to the continued application of maximum torque. Under such conditions good suspesnion and driveline components are required to keep the suspension calm. When wornm massive vibrations/movements are allowed in the wrong directions and no balance can be found. A rough surface makes this much much worse on the system.

In the old days this was perhaps described partly as axle tramp, but in a BMW's case the suspension is a little more complex. Whatever one might call it; tramp/yore/yack...- it is bad and if you were the car you might know it as feeling slight grabs as the tyres grip and then slip/bounce 5 times a second as your suspension rips around in directions that would normally be far more adequately damped/maintained.

I've only blown one centre bearing myself (but it was from this not wear) so it **is only a theory** so far.

However if one side of your car has bad trailing arm bushings you might have the real root cause. This is strange (esp in one side) they normally last for damn near the life of the car. However they would amplify the problem described above. Perhaps there is a cause for this. Replace and align. The arm might be bent- this is common when people have backed into something or the car has sustained a whack on one side. Perhaps from a spirited over-correction too many or perhaps from hitting a gutter... either way if you're trailing arms bushings are gone it is unusual and needs to be checked- up to the point of passing specification on a 4 wheel aligner.

I'll put my money firmly on a new trailing arm. I hate the sound of you running the car free-wheeled on stands though. Scares me to death: I see news reports claming "Car drives through house, kills GrandMa and the family dog"... though I know hunting a problem like this requires drastic action. Just remember, no court would look kindly on a BMW driver doing their own maintenence. They think we are bad enough passing them in the traffic and should have to pay through the teeth for professionals to fix any car this much nicer than theirs...

Good luck, be careful and let us know how it ends up! :) Nick

[stargazer_61]

technical definitions Glossary:

Whack: a non denominational term to desribe a measure of mechanical distance or relativity that is undefinalbe yet understood globally as a unit of measure or level of fuk up.

Now THAT's funny!

But seriously, I followed the procedure as described here:

http://www.bmwe34.net/e34main/Maintenance/Transmission/CenterBearing.htm

If I am understanding you correcty, then I did not misalign the splines when bolted back together. I did have them misaligned when I first inserted the splined shaft into the end, but this was totally obvious by the look of the alignment marks, and I pulled it apart and turned it to match up.

[stargazer_61]

I reckon your centre bearing could be blown again. they are weak as piss, so any trouble down the back breaks them at the joint where their pissy outer carrier welds to their pissy little bracket. They really aren't designed to take load. If they do something else is wrong. No matter what after you isolate the root cause, you might find the centre bearing's mounting is fatigued or damaged.

I'll go out on a limb here with a little theory; (form the last failiure in mine) Bad dogbones ie pitman arms can blow the centre bearing when a lot of power is applied and excessive oversteer induced.

As the car slides, should the driver try to regain acellerational control without backing off the throttle straight away, severe jagged stresses are induced in the driveline. With the tyres fighting for traction and the driveline preventing this through more the application of too much torque, these components cannot keep the suspension calm. Massive vibrations are allowed in the wrong directions inside the rear arms and no balance can be found. A rough surface makes this worse.

In the old days this was perhaps described partly as axle tramp, but in this case teh suspension is a little more complex. Whatever one might call this; tramp/yore/yack... whatever, it is bad and if you were the car you might know it as feeling slight grabs as the tyres grip and then bounce 5 times a second and your suspension rips around in directions that would normally be more adequately damped.

I've only blown one centre bearing myself from this so it is only a theory so far.

However if one side of your car has bad trailing arm bushings you might have the real root cause. This is strange (esp in one side) they normally last for damn near the life of the car. However they would amplify the problem described above. Perhaps there is a cause for this. Replace and align. The arm might be bent- this is common when people have backed into something or the car has sustained a whack on one side. Perhaps from a spirited over-correction too many or perhaps from hitting a gutter... either way if you're trailing arms bushings are gone it is unusual and needs to be checked- up to the point of passing specification on a 4 wheel aligner.

I'll put my money firmly on a new trailing arm. I hate the sound of you running the car free-wheeled on stands though. Scares me to death: I see news reports claming "Car drives through house, kills GrandMa and the family dog"... though I know hunting a problem like this requires drastic action. Just remember, no court would look kindly on a BMW driver doing their own maintenence. They think we are bad enough passing them in the traffic and should have to pay through the teeth for professionals to fix any car this much nicer than theirs...

Good luck, be careful and let us know how it ends up! :) Nick


Those carrier bearings are pretty crappy, especially considering the stresses that they are put under. One would think that they would be built better. I looked at it yesterday, after I started this thread, and it hasn't broken, at lest not yet.

Today I am picking up some new dog bones, and while installing, will clean and further inspect the trailing arm bushings. I only took a cursory look at them, and it could have merely been road crud and not cracking. The tire wear on the inside of the tread looks pretty even on both tires, and I would think that if the trailing arm were bent, the wear would show a pattern for failure. While the rear tires were off, I grasped the trailing arm and gave it a few good jerks, and it seemed pretty solid, but I will definitely have a close look at it.

Crawling underneath whilst free wheeling is certainly something I do not take lightly, as no sane person should, but sometimes necessity dictates, as you pointed out, Nick. I appreciate your concerns your advice, and your technical explanation of the stresses the rear suspension undergoes during hard driving.

[genphreak]

No worries mate. It's the kinda thing none of us like but the sort of thing anyone owning a car like these has to go through at some point...

If not the arm, what could be the cause? My theory about pitman arms (combined with bad shocks) was the problem for me. Though I haven't been sideways much since it all went 'woop'. Howeer now I ahve a spare centre bearing, so can afford to get a bit more 'imaginative'. If you hear mine's gone again, it'll prove my theory is all shot and put a mark agianst the centre bearing's design. However, given that these bearings are used on virtually all Bimmers, I think it is really not under the kind of stress we might imagine (after all the diff is very solidly mounted)- so it is really there for tolerances and to take up any body/engine/component twist.

If your tranny mounts, engine mounts and so on are all good it really only leaves a question mark over your shocks, how good are they?

Of yea, and for you to come clean about how much of a burn out you were really doing!! ;)

[stargazer_61]

No worries mate. It's the kinda thing none of us like but the sort of thing anyone owning a car like these has to go through at some point...

If not the arm, what could be the cause? My theory about pitman arms (combined with bad shocks) was the problem for me. Though I haven't been sideways much since it all went 'woop'. Howeer now I ahve a spare centre bearing, so can afford to get a bit more 'imaginative'. If you hear mine's gone again, it'll prove my theory is all shot and put a mark agianst the centre bearing's design. However, given that these bearings are used on virtually all Bimmers, I think it is really not under the kind of stress we might imagine (after all the diff is very solidly mounted)- so it is really there for tolerances and to take up any body/engine/component twist.

If your tranny mounts, engine mounts and so on are all good it really only leaves a question mark over your shocks, how good are they?

Of yea, and for you to come clean about how much of a burn out you were really doing!! ;)

The rear shocks could be an issue, the left rear feels kind of soft, and after looking at the car from the rear, the angle between top & bottom of the wheels is noticeable. Tranny & engine mounts are new within the past couple of months.

As for the burn out, well, I will confess to only a couple of hard launches from standstill in sport mode, which is always a treat! No scratch marks on the pavement. it just feels like a hole shot. Most of the fun was on the nice, twisty road at 70-90mph, with slowing & hard acceleration for nothing but the sheer joy of being pasted to the seat & watching the tacho jump to 6k!!

[nma]

i don't mean to hijack your thread but found it very interesting that i am having the same problem as you and have been trying to solve it forever now!

well, if it helps to eliminate some of the possible problems, and of course, maybe i can try some of the suggestions/solutions here as well.

the vibration on my car comes when the car is being loaded, from rolling up to about 25-30mph. it gets worse when i have more people in the car, when i turn to the left and/or climb up a slope. the sound appears to be coming from the rear left hand side or maybe in the d/s well. it's hard to pinpoint the source exactly. one thing i found different from your issue is i would get a loud thump if i backup really fast - not immediately after dumping the clutch but as the suspension unload fast. the vibration started last year, after a very hard launch and i've not been able to get it to end!!!

so here's some of the solutions i have tried and still haven't got it solved.

1. took out, inspected and re-tightened rear diff (LSD).
2. replaced guibo
3. replaced center bearing
4. replaced RSM
5. replaced subframe bush
6. replaced pitmann arm bush
7. turned two halves of the d/s 180 degrees.
8. rebalanced rear wheels
9. took out, inspected, re installed rear shocks
10. added 2 additional mounts on my gear box (5-sp dogleg)

the knuckle on the d/s (uni-joint) has some play (about .5mm) along one of the joints but i doubt this is the source of the problem. it would have produced big vibrations at high speed if that's the case. no seizure when turning the d/s. d/s was balanced about a year ago.

however, i have small vibration at speeds above 80mph and feels like the tail is wiggling... kinda like a free butt massager there :)

what i haven't done and am thinking about doing are:
1. replace trailing arm bushes (good suggestion nick). it looks like the left camber is more than the right one at the moment. so i'm crossing my fingers on this. could this be the source of the loud thump? and the vibration?
2. replace output shaft
3. change a new d/s
4. drive the **** out of it until something breaks. it's a really tiring process and it feels like it's going nowhere.

so please keep posting and share your experience. i'll try to do the same.

thanks people.

btw, i love this board. have been a lurker for quite sometime now. great info!

[stargazer_61]

Well, I finally got around to replacing the entire driveshaft. U-Joint was binding, causing all of the problems with it. Though there was no radial play, the joint was stiff along one axis and I presume that under load was causing more problems than I could create by working it with my hands.

For those of you in NC, Oliver's Driveshaft in Winston-Salem ordered it for me and I got it for what I think is a reasonable price of $360 with center bearing & new CV gasket. They have a good rep with the 4x4 crowd and were honest enough to say that they'd rather not touch a BMW because they just can't get them done to their satisfaction. $100 less than quotes for a rebuild of the joints.

Some things discovered in the process:

1) When dropping the exhaust on 540's, it is much easier to disassemble the cats from the pre-muffler, dropping them first, then the back half. Bloody thing is way too heavy to work with whole.
2) Double-check the alignment of the gearbox/driveshaft in the tunnel. Mine was a bit off
3) Check the condition of the centering bushing. Mine was trashed
4) Raise the car up on all 4's - Ramps up front, jackstands at rear. Plenty of room to work with
5) Flow BMW in Winston does not stock the 16mm self locking nuts for the final drive for some strange reason

Bottom line is that the car now performs as it should. Smooth acceleration, pressing me into the seat. No funky noises. I wasted some time/money not just biting the bullet on a new driveshaft.

[yaofeng]

I am not clear in the end what did you find the culprit which caused the vibrations. And where is the centering bushing?

[Dave M]

Apparentley U-Joint was binding, causing all of the problems. Not sure how a stiff U-joint could do this, but I assume the driveshaft folks in NC came to that conclusion.

Great thread from start to finish. Thanks for providing the update, it will come in handy in the future.

Dave M

[stargazer_61]

I am not clear in the end what did you find the culprit which caused the vibrations. And where is the centering bushing?

According to Anthony at Oliver's, when the joints bind you will get a wretched vibration. I presume because the driveshaft is not flexing correctly under load, this causes it to be off center as it enters the center bearing, putting stress on the left-hand side of the metal ring supporting the rubber. This is what always broke on me.

The centering bushing is pressed in to the front of the driveshaft. It centers it on the output shaft of the transmission. It is a metal ring with a rubber center. The sleeves on the guibo will not properly center it. It is a special order item from the dealer because they typically do not go bad by the time the driveshaft is replaced. My new one came with one, fortunately.