Author Topic: Driveline hum/vibration exponentially worsening-whole car shakes HELP (Read 4549 times)

schmall's supe · « **on:** February 15, 2013, 10:34:53 PM »

So I have a stock 1991 318is about 120k miles I replaced the csb and balanced the driveshaft when I first got it a year ago everything was fine for 15k miles.

Lately(last month), I have been noticing some slight driveline vibration, especially at the low end of 4th and fifth nothing serious, I attributed it to some shot transmission mounts(they were visibly broken). I ordered some new mounts from rock auto and put them in wedensday. The jack I used to support the tranny while swapping mounts drooped and let the drivetrain hang solely by the engine mounts. I didn't think too much of it but I knew it could be bad news for the motor mounts.

Car felt okay at first vibration was gone in 4th and fifth altogether. But now 1st and 2nd feel horrible. Terrible vibration, steering wheel vibrates so much at 25 in 2nd that it visibly moves around about a mm.

So I figured shoot that lousy jack must of let my driveline sag and broke my motor mounts. So I grab a pair of e28 mounts cut off the tabs and put them in this evening.

Now the vibration I was feeling is even worse , when I floor it in 2nd or 3rd it feels like an earthquake.

Could it be by quibo I saw a few cracks in it but it didn't look as serious as the vibration im feeling. Could I have installed my transmission mounts wrong? they had little alignment tabs that face the back I don't think it was possible to put them in wrong. The motor mount tabs on the frame looked fine.

What could be going on??

keflaman · « **Reply #1 on:** February 16, 2013, 06:18:38 AM »

I've been searching for the cause of my driveline vibration for almost a year. It's not as severe as you describe, but after installing a pair of perfectly round and balanced tires in the front, the car rode noticeably smoother.

I drove to work in a decidedly more spirited fashion enjoying the crisp handling of my beloved little car. I pushed a couple of sharp, left-handed corners REALLY HARD and worked the suspension like never before.

When I left work that afternoon I had to pull to the side of the road within a quarter mile because I swore someone must have loosened the lugnuts on the car!:eek:

I am at wits end trying to figure this out and I have replaced the exact same things you have mentioned and much, much, more. New motor/tranny mounts, CSB, CABs, and every single frickin' rubber piece from the front to rear bumper. Two complete, different sets of tires and rotated two different spare tires into the mix trying to isolate, eliminate, and/or compensate.:mad:

I have new ball joints coming today that I will install, but I've tried two different sets of control arms and none of the joints on them appeared worn; in fact, one set had only 20K documented miles on them.

My vibration problem differs from yours in that I don't remember the vibrations being worse during acceleration, but I'll take it out and verify that today.

In summary, I have noticed the vibrations seem to differ after hard, straight line braking or pushing in the corners, so something has to be shifting and throwing things out of alignment. I checked the tranny to see if it was centered in the tunnel and depending on how I measured it COULD be off center by MAYBE 3/16". I'll try checking alignment of the entire driveline with a plumb bob today.

Well, maybe not today as I'm hosting a fender-rolling GTG in a few hours.

Update: Took some rough measurements and the engine and diff look to be square to the car's longitudinal axis. I took a look in between the heatshields and floor panels with my borescope and it appears that the CSB metal frame is misaligned. The left side bolt is sitting at the rear of the slot and the right side is sitting in the slot with proper pre-load.

schmall's supe · « **Reply #2 on:** February 16, 2013, 09:45:11 AM »

Hav you recently replaced the csb? Balanced the driveshaft? Does the vibration cease when you take it out of gear and let it coast at 40-50 or while taking in a corner not in gear?

Damn though sorry to hear about replacing all those parts and still chasing the issue it can be so frustrating I know.

Im going to check out my csb and will report back with findings.

colin86325 · « **Reply #3 on:** February 16, 2013, 10:40:47 AM »

It would be worth checking your wheel bearings, though most (not all) of the time they make noise when bad.

keflaman · « **Reply #4 on:** February 16, 2013, 07:40:15 PM »

Sorry OP, I didn't mean to hijack your thread, but I appreciate your suggestions.

There doesn't seem to be a difference between coasting or under load. I've never tried coasting through a corner.

I replaced the left rear bearing and the right was replaced before I bought the car. I've looked for any play in the front bearings and not found any. I have noticed they spin very freely...is that normal?

deansweet · « **Reply #5 on:** February 16, 2013, 07:51:16 PM »

Quote from: keflaman;120185

I have noticed they spin very freely...is that normal?

Since it's only been a couple hours since I was showing my brother how easily the front wheels of my 318is spin with zero noise?! He's an american car kind of guy and is used to dragging of pads, grinding of bearings, etc. So the answer to your question is yes, the spin very freely.

-Dean

doitover · « **Reply #6 on:** February 16, 2013, 09:44:32 PM »

Next to no experience with this but I did have a vibration in mine that I would have sworn was the driveshaft. It was did all the u-joint things, it even seemed to rumble on deceleration. It turned out to be a bent rim.

keflaman · « **Reply #7 on:** February 17, 2013, 06:23:30 AM »

Quote from: schmall's supe;120166

Hav you recently replaced the csb? Balanced the driveshaft? Does the vibration cease when you take it out of gear and let it coast at 40-50 or while taking in a corner not in gear?

Damn though sorry to hear about replacing all those parts and still chasing the issue it can be so frustrating I know.

Im going to check out my csb and will report back with findings.

When you rebalanced your driveshaft, did you replace the centering sleeve, P/N 26 11 7 526 611? (#1, http://bmwfans.info/parts/catalog/E30/2-doors/USA/318is-M42/LHD/M/1990/july/browse/drive_shaft/drive_shaft_univ_joint_centre_mounting/).

I don't think I've never seen cracks in a guibo except for brand new ones.

I replaced the aforementioned parts mainly in the interest of preventative maintenance. The car had 155K when I picked it up and I decided on a total refresh of the suspension. The vibration has always been there, but more recently it seems to ebb and flow depending on how I drive it.

I have two good rims on the way and ball joints are sitting on the work bench now. I'll press them into another set of control arms at work this week.
I replaced the CSB last summer, but I think I'm going go back to that area and rotate the driveshafts 180*.

Dean, I swear I could give my front wheels a whirl, leave for lunch, and come back to find them just winding down. Maybe that's why we get such good mileage? Glad to hear that's normal.

keflaman · « **Reply #8 on:** February 19, 2013, 02:42:55 PM »

Can blown out sway bar bushings effect a vibration?

colin86325 · « **Reply #9 on:** February 19, 2013, 03:20:13 PM »

No, sway bushings wouldn't cause that type of problem.

keflaman · « **Reply #10 on:** February 20, 2013, 05:17:36 AM »

Darn. Well, at least it tracks flatter in left hand turns now.

After pulling the exhaust shields and getting a clear look at the CSB, I saw that it wasn't misaligned like it appeared to be. I was going to pull the driveshaft and rotate the halves 180*, but decided it was too much work at this point. Instead, I rotated the front half between the guibo and tranny output shaft counterclockwise one bolt. By all accounts, it seemed to help, but I'm attributing that to the placebo effect for now. We'll see what I think after a few days of driving.

deansweet · « **Reply #11 on:** February 20, 2013, 07:01:02 AM »

I know this sounds crazy but have you checked the lower ball joints on front control arms?
Take front wheel off the ground and see if it has any play? Could be when you transfer weight front to back during acceleration it's allowing the front end to 'wiggle' especially in steering wheel.

keflaman · « **Reply #12 on:** February 20, 2013, 12:51:58 PM »

Quote from: deansweet;120290

I know this sounds crazy but have you checked the lower ball joints on front control arms?
Take front wheel off the ground and see if it has any play? Could be when you transfer weight front to back during acceleration it's allowing the front end to 'wiggle' especially in steering wheel.

I sure did, in fact, this is the second subframe I've installed and didn't notice play in either one.

I wonder if I have the front lowered just too much? I've checked the toe-in several times and it seems to be correct. I've even performed a four-wheel alignment at least twice.

It's not really even a vibration any longer; you can see it in the rearview mirror more than feel it in the steering wheel as a low frequency buzz. If that makes sense.

I wish they made a vibration tester for cars like we have for helicopters and airplane props.

schmall's supe · « **Reply #13 on:** February 22, 2013, 10:46:25 AM »

Ok got my vibration eliminated, replaced guibo with a good ol rockauto unit, everything is smooth as glass now. My old one had visible cracks on 40% of it. Those e28 mounts are lil bit rougher then i expected from reviews on them. But which ever at least i can get around without having to worry about the driveline destroying itself. Thanks everyone.

keflaman · « **Reply #14 on:** February 22, 2013, 06:38:59 PM »

I'm glad you found your problem and it was a cheap fix.

After swapping out half a dozen tires and close inspection...I apparently don't have one round tire in the lot!! Almost every tire has a flat spot, so once I receive the last basketweave coming to me I'll get everything mounted and shaved.