[Efthreeoh]

So 10 days ago I noticed a vibration in the drivetrain under full throttle and from around 4,000 RPM to redline. I can feel it in the shifter (manual transmission), but the strange thing is it really sounds like it could be an exhaust issue. With the mechanical vibration is also noise, which sounds similar to a 335i when the blow off valve activates. When accelerating hard and reaching 4,000 RPM the vibration comes up, I shift to the next gear (it's in 4th gear at that engine speed when it is really noticeable) the noise subsides a bit. I've left the car at high revs in 4th and 5th and the vibration stays in the background but stabilizes, and the noise seems to go away.

I first noticed the car picked up the vibration after I went though an automatic car wash when it was around 5 deg. outside, so I thought maybe the hot exhaust cracked somewhere when it with the cold water for the chassis wash part of the wash cycle. It's probably just a coincidence anyway.

I threw it up on the lift yesterday and inspected the exhaust, checked the transmission oil level (it was good), looked at the drivetrain and exhaust mounts (all looked normal), and checked the halfshafts (good and tight). I rotated the rears and the diff sounded good.

Considering the car has 240,000 miles on it, it's probably a worn part somewhere. So my thoughts are:

- driveshaft center bearing
- bad hydraulic engine mount
- maybe a broken baffle inside the muffler
- guibo (it looked in good shape a year ago)

Looking for thoughts from you guys.

Thanks in advance.

At that mileage it might be a good idea to replace the bearing and both guibo's since the labor is the same and the parts are cheap.

If you haven't replaced your motor/trans mounts I would do those too.

My passenger side motor mount was shot @ 90k miles on my 330i, I replaced both with the upgraded 335is one see my thread. This only gave me vibrations at idle.

Trans mounts are like $17 a piece are are easy as pie to replace.

[Efthreeoh]

Originally Posted by index1489

At that mileage it might be a good idea to replace the bearing and both guibo's since the labor is the same and the parts are cheap.

If you haven't replaced your motor/trans mounts I would do those too.

My passenger side motor mount was shot @ 90k miles on my 330i, I replaced both with the upgraded 335is one see my thread. This only gave me vibrations at idle.

Trans mounts are like $17 a piece are are easy as pie to replace.

Thanks. I remember your thread about it. At idle I don't notice a vibration, so I'll rule out an engine mount as a first-order issue. But I do plan on replacing the center bearing and guibo (heck, maybe it broke due to the cold weather). And your right, it can't hurt to do the trans mounts too.

Thanks for the input.

[Efthreeoh]

So a bit of an update:

My driveshaft parts finally came in after 5 weeks wait for the center bearing. I replaced the center bearing and rubber flex joint (we used to call it a guibo), and the transmission mounts. The driveline got a bit smoother, but the vibration I was originally talking about was getting better as the miles racked up anyway, so all in all not a big change. The center bearing was a bit loose but not too bad. I may do the engine mounts just to be sure, and maybe the diff mounts too. I still think what happened was an internal baffle in the muffler broke back in February and was/is causing the vibration. Or it could be the diff is going, but I'm not so sure. If it does after 246,000 miles, I'll rebuild it with an LSD. I'll keep you posted on it.

Now what I did discover is this. The driveshaft has two small plastic isolators ("damper rings") that sit on the splined part of the shaft (Item #5 in the pic below). My driveshaft when I disassembled it did not have these parts in it. Being confused that it didn't, I was leery to put both new parts in (I was smart enough to order them for some reason), so I just put one in instead of two; I was concerned the shaft would not collapse far enough to reinstall it. Well low and behold the metallic clink that some of us hear when we load and unload the drivetrain has now gone away. I think these two little plastic damper rings were added to the drive shaft assembly to prevent the noise.

You can pick up a used diff @ car-part.com for cheap from a low mile car, just got to do the research on the final drive ratio you want, I would suggest doing the passenger side motor mount first as its the primary wearing one see if anything changes.

You can pick up used oem mufflers on there or here on the forum aswell.


I would do the muffler and motor mounts before messing with diff.

[Efthreeoh]

Another update:

So the original vibration I was concerned about is now completely gone. I'm almost 100% convinced it was related to the exhaust. I think a baffle or possibly the innards in one of the secondary cats broke loose and has now finally disintegrated where it is no longer making noise. Considering the exhaust has one mounting that attaches to the rear trans mount, it may have been the path of vibration from the exhaust up to the shift lever. Wait long enough and rack up the miles and you get a performance exhaust for free

The center bearing and new guibo helped quiet the driveshaft, not surprising since new parts are always good . As far as the diff is concerned, that has seemed to quiet down too. The rumble I've been hearing may be the right front wheel bearing; it's been making bad noises at low speeds and sharp turns. I picked up my new wheel bearings yesterday and will install later his afternoon.

Ah, the pleasures of BMW ownership at 248,000 miles.

[Efthreeoh]

Originally Posted by index1489

You can pick up a used diff @ car-part.com for cheap from a low mile car, just got to do the research on the final drive ratio you want, I would suggest doing the passenger side motor mount first as its the primary wearing one see if anything changes.

You can pick up used oem mufflers on there or here on the forum aswell.


I would do the muffler and motor mounts before messing with diff.

Yeah, I agree. I may pull the motor mounts, or at least jack the motor up, and check them today. I plan also to run the drivetrain today and look and listen to the diff too. A remanufactured diff from BMW is only $1,500, which I don't find too terrible of a price to be honest. I've also considered that if the diff is bad, I have a local shop that can rebuild it with a LSD kit, so we'll see.

[Efthreeoh]

Update and problem finally solved.

So just to refresh, starting around February 2014 at 248,000 miles I noticed a drivetrain vibration at high RPM shifting. I chased it down by installing a new guibo (rubber isolator between the drive shaft and transmission) and a new center bearing. Those parts helped a bit, but the vibration was still there. About a year ago a new vibration issue came up which was a vibration at idle. The vibration was like a lumpy idle, but the actual cylinder firing was very smooth. In November of 2014 I had the car in to a BMW dealer to set the alignment and I requested the Tech look into the lumpy idle. His diagnosis was a bad coil, but I discounted that diagnosis since I had no SES trouble codes. I assumed he was looking for an easy $600 coil job. Well in August 2015, I lost coil No. 5, so I replaced the rack of coils and new plugs at 286,000 miles. The lumpy idle was still present. Upon the suggestion of a fellow E90 Poster, I then replaced the crankshaft vibration damper back this past summer and still had the lumpy idle, but the engine was a bit smoother. So I suspected either the engine mounts or the flywheel.

So the fix... I finished replacing the clutch today along with a new dual-mass flywheel. I installed a new LUK flywheel, which is the OEM part. Sure enough I can report in the new flywheel was the fix. I've now researched and discovered that the dual-mass flywheels can fail during the lifespan of the clutch. The motor revs smooth as the day it was new. And it is nice having a light clutch pedal again.

Cheers.

[PichaDis11]

Originally Posted by Efthreeoh

Update and problem finally solved.

So just to refresh, starting around February 2014 at 248,000 miles I noticed a drivetrain vibration at high RPM shifting. I chased it down by installing a new guibo (rubber isolator between the drive shaft and transmission) and a new center bearing. Those parts helped a bit, but the vibration was still there. About a year ago a new vibration issue came up which was a vibration at idle. The vibration was like a lumpy idle, but the actual cylinder firing was very smooth. In November of 2014 I had the car in to a BMW dealer to set the alignment and I requested the Tech look into the lumpy idle. His diagnosis was a bad coil, but I discounted that diagnosis since I had no SES trouble codes. I assumed he was looking for an easy $600 coil job. Well in August 2015, I lost coil No. 5, so I replaced the rack of coils and new plugs at 286,000 miles. The lumpy idle was still present. Upon the suggestion of a fellow E90 Poster, I then replaced the crankshaft vibration damper back this past summer and still had the lumpy idle, but the engine was a bit smoother. So I suspected either the engine mounts or the flywheel.

So the fix... I finished replacing the clutch today along with a new dual-mass flywheel. I installed a new LUK flywheel, which is the OEM part. Sure enough I can report in the new flywheel was the fix. I've now researched and discovered that the dual-mass flywheels can fail during the lifespan of the clutch. The motor revs smooth as the day it was new. And it is nice having a light clutch pedal again.

Cheers.

Thanks for sharing the outcome. Took a year but you handled it.

[Efthreeoh]

Originally Posted by PichaDis11

Thanks for sharing the outcome. Took a year but you handled it.

Two years actually. Once I put the new vibration damper on I pretty much was convinced it was the dual mass flywheel. I didn't have time until last week to do the "operation". With a 250,000+ mile BMW, the last you do is chase down issues with parts = money.