Vibration while decelerating?

**bavdrftr318** · 01-02-2013, 07:10 PM

Originally Posted by dinanstu

Did you check the clutch/flywheel combo? It may be worth it to have it removed, inspected and balanced...

Nope hasn't been balanced. Clutch is a Southbend Stg 5 and i have a stock dual mass flywheel. Realistically I'm going to have this and the DS professionally double checked and balanced to completely rule them out.

Originally Posted by killaM3

it might be silly, but front control arms bushings and balljoints are known to cause vibrations on braking when they are on the way out. check that.

Brand new control arms, bushings, and tie rods. Can't be that.

**rocky999** · 10-26-2017, 10:22 PM

Revisit to an old thread. I struggled for a year plus trying to rid the E36 M3 of the deceleration driveline vibration. 2 New flex disks, balanced drive shaft, readjust The CSB, re-torgue the trans mounts to name most. FINALLY it turns out to be the vertical drive shaft alignment. I used a bubble torpedo level and shimmed the level till the back section of the shaft showed level on the level. Then compared the front section. It was off 1/2 bubble. I shimmed the CSB mount with a couple of thick washers and got the front angle very close to the rear section, about 4 mm total thickness. Viola no more vibration!! Wish i had a digital level to get it closer, but it is now close enough to eliminate the vibration. Best to all struggling with the decel vibration. This might be worth a try.

**euro2fast4u** · 10-27-2017, 12:15 PM

check the tq of the wheel lugs?

**testify** · 10-27-2017, 12:19 PM

I have the same problem as OP. My cause is a worn tail flange bearing on the transmission. There is a little up and down, side to side play in the flange.

I'm curious weather the bearing can be replaced from outside the trans, or whether the case need to be split and disassembled to get at it.

**Def** · 10-28-2017, 02:41 PM

Tail flange? You mean pinion bearings? You'll have to press the pinion out in every IRS or third member diff I've seen. That means dropping the diff and disassembling it. You should recheck the pinion depth and pinion to ring gear contact after replacing the bearing, as well as pinion bearing preload if you don't have a crush sleeve in there (I think most modern BMWs use a crush sleeve tho). It's not super hard, but I wouldn't call it a simple job if you've never taken apart and setup a diff. You need a press to do the work as well.

**jakermac** · 10-28-2017, 07:24 PM

He’s talking about the tailshaft bearing in the transmission, at the front of the driveshaft.

**SUVETR** · 04-12-2020, 01:55 PM

Originally Posted by rocky999

FINALLY it turns out to be the vertical drive shaft alignment. I used a bubble torpedo level and shimmed the level till the back section of the shaft showed level on the level. Then compared the front section. It was off 1/2 bubble. I shimmed the CSB mount with a couple of thick washers and got the front angle very close to the rear section, about 4 mm total thickness. Viola no more vibration!!

Yet another thread revival! rocky999, your experience seems to be similar to mine. Thanks for this info, as it presents SOMETHING I haven’t tried yet. Trying to understand your description. Are you basically saying that you aligned the CSB so the entire driveshaft it is one straight line from the trans to the diff?

I’ve had numerous attempts to replace almost everything. Guibos, CSBs, rebuilt/balanced driveshaft, clutch/pp/flywheel, rebuilt diff, etc. But this vibration has been there for years and I’m going a bit batty trying to figure it out. The only thing I haven’t attempted yet is to replace the crank damper on the front of the engine. Aligning the driveshaft would be a lot easier, so will give that a try!

My vibration is also only on decel. Not every time, either. But frequently. And when it happens, you know it. Very noticeable. It isn’t totally predictable but it seems more likely to happen if you lift off abruptly. A light touch on the accelerator makes it immediately go away, and lifting off the throttle extra-gently seems to be the best way to keep it from happening.

I have ultra-stiff Vorshlag motor/trans mounts, and poly diff/subframe mounts. But the slight increase in in NVH from these things is clearly NOT what we’re talking about, here.

**Clifton23** · 04-26-2021, 10:59 AM

Originally Posted by SUVETR

Yet another thread revival! rocky999, your experience seems to be similar to mine. Thanks for this info, as it presents SOMETHING I haven’t tried yet. Trying to understand your description. Are you basically saying that you aligned the CSB so the entire driveshaft it is one straight line from the trans to the diff?

I’ve had numerous attempts to replace almost everything. Guibos, CSBs, rebuilt/balanced driveshaft, clutch/pp/flywheel, rebuilt diff, etc. But this vibration has been there for years and I’m going a bit batty trying to figure it out. The only thing I haven’t attempted yet is to replace the crank damper on the front of the engine. Aligning the driveshaft would be a lot easier, so will give that a try!

My vibration is also only on decel. Not every time, either. But frequently. And when it happens, you know it. Very noticeable. It isn’t totally predictable but it seems more likely to happen if you lift off abruptly. A light touch on the accelerator makes it immediately go away, and lifting off the throttle extra-gently seems to be the best way to keep it from happening.

I have ultra-stiff Vorshlag motor/trans mounts, and poly diff/subframe mounts. But the slight increase in in NVH from these things is clearly NOT what we’re talking about, here.

Same exact issue I am having with almost the same setup as you. Slight blip of the throttle fixes the vibration normally. I have replaced almost everything but I haven't tried rocky999's solution.

**fatherharbin** · 08-21-2021, 08:33 PM

Here to ask of anyone else's opinion but I've had this problem since I swapped a zhp motor into my 325i after it blew up and installed 80a engine/trans mounts. My car now has an extreme vibration that feels like your driving over massive rumble strips when I hit 3k on decel. Ive got 209k on the chassis but it was very well kept. My only clue is that when I blew my motor I over revved from a money shift and while the car was still rolling I tried to take a turn and my rear end slipped out from behind me on a slightly wet day. Curious as to why my car is making a distinct vibration/shudder, I haven't really taken a look at the rear. Thanks!