Driveline shudder

kasbatts · Nov 22, 2014

Hi all,

I have a driveline shudder in the car when moving away from a standing start in 1st gear.

Car has just had gearbox bearings replaced, new rubber donut, rebuilt driveshaft (and balanced) and new centre bearing (preloaded)

Shudder is only at very low speed (approx 20mph) in first gear, no problems when car is up and moving.

I read another post from back in 2011 where someone mentioned "the usual driveline shudder these cars suffer"

Any idea's on this??

Steve

Stevehose · Nov 22, 2014

textbook symptom of the center bearing, may want to recheck that and the guibo. Also given your transmission fit issue the driveshaft may be out of alignmnet between transmission and differential.

adawil2002 · Nov 22, 2014

Something is out of alignment or out of balance. Shouldn't make any noise or shudder.

sfdon · Nov 22, 2014

Some thoughts for you...

The center bearing is preloaded not the "donut"
5 speed tranny swaps have a common issue if they include upgrading to a modern style of "donut".
Unless you drilled the opening of your driveshaft (the nose) or cut off a bit of your tranny output shaft your "donut" is probably bent like a huge wavy washer.
If you used the old style 45mm unit it's not a problem.

mr bump · Nov 22, 2014

I would say the clutch is at fault, probably a slight flat spot?

kasbatts · Nov 22, 2014

adawil2002 said:
Something is out of alignment or out of balance. Shouldn't make any noise or shudder.

Hi adawil,

Alignment is good, spent quite a bit of time making sure this was good, balance is also good, when driving at all other speeds it is perfect, no shudder or driveline vibrations.

sfdon said:
Some thoughts for you...

Hi don,

The center bearing is preloaded not the "donut"

Yes, correct, typo sorry.

5 speed tranny swaps have a common issue if they include upgrading to a modern style of "donut".

Unless you drilled the opening of your driveshaft (the nose) or cut off a bit of your tranny output shaft your "donut" is probably bent like a huge wavy washer.

Driveshaft nose has been drilled and the donut is perfectly flat and has no undue "twisting" load on it from anything being out of align.

mr bump said:

I would say the clutch is at fault, probably a slight flat spot?

Click to expand...

Clutch is smooth all the way through the release, the shudder comes in after the clutch is released and I am just applying acceleration.

Thanks guys for your response's, will go and have a head scratch and see if I can come up with anything, think I will check the preload on the centre bearing again, what is the official figure for this? I have read 2mm from some people and up to 1/4 inch quoted by others.

Steve

sfdon · Nov 22, 2014

Could be a bad spring in the clutch disk. They do break.
Your clutch could also be sticking on the tranny Input shaft - was it greased on install?
About 3 yrs ago a bunch of t/o bearings came out were out of spec- too small on the ID and they were sticking on the tube.

Ian C · Nov 22, 2014

Steve, when the diff mount cracks through a bolt hole,( usually rear right ) it allows the diff to flop around and can feel like clutch judder. Coupkings website has some good info on this problem. I hope thats not it because it is a pain to repair. Ian.

Honolulu · Nov 23, 2014

Were it me I'd jack up the back wheels, run the car in first gear at idle (wheels spinning) and climb under to have a look.

But that could be really really dangerous, so I didn't say it, any impression that I did or might have is certainly erroneous, and I won't do it again.

Recently helped a pal sort his salvage title (engine fire) Tacoma pickup with came with a dented driveshaft (wobbles at speed) and a bent left rear axle (judder in brakes, unstable braking, really bad juju, sent him into the median for mucho bodywork). We jacked it up, ran the truck at idle, got under to discover the dented driveshaft, later stood alonside the spinning rear wheels to discover the bent axle.

Stevehose · Nov 23, 2014

Because the symptom is 1st gear from standing start, something is torquing from the mass of the car. Once moving, not enough force present to cause the problem. So I think some mount or bearing along the driveline is slightly shuddering under heavy load.

sfdon · Nov 23, 2014

Was the center bearing installed backwards? They are asymmetric.

lloyd · Nov 23, 2014

Stevehose said:
Because the symptom is 1st gear from standing start, something is torquing from the mass of the car. Once moving, not enough force present to cause the problem. So I think some mount or bearing along the driveline is slightly shuddering under heavy load.

Agree that so-called shudder is most often caused by worn center support bearing and/or disintegrating or severely worn guibo. Since you have evidently eliminated these items from your checklist, you could have a loose, worn or broken motor mount and/or transmission mount. As unlikely as it may seem, the subframe upon which the engine mount is bolted (nearest the steering gear assembly) could fatigue and crack under severe duty. I mention this only because I recall seeing that area of the frame gusseted on an E9 track car with the explanation that it was "a necessary ounce of prevention."

Transmission cross member mounts are notorious for looking fine although in actuality, the mount is severed in two. Alternatively, the mount can be putty-soft, and practically useless. I suppose if a little unwanted grease or oil made its way onto the clutch surface, clutch engagement may not be as smooth as it could be.

http://www.e9coupe.com/forum/showthread.php?t=14861

http://blog.bavauto.com/14153/bmw-v...ile-accelerating-center-bearing-or-flex-disc/

kasbatts · Nov 23, 2014

sfdon said:
Could be a bad spring in the clutch disk. They do break.
Your clutch could also be sticking on the tranny Input shaft - was it greased on install?
About 3 yrs ago a bunch of t/o bearings came out were out of spec- too small on the ID and they were sticking on the tube.

Hi Don, Clutch is well greased on the input shaft.
Its a clutch that's been in the car a few years and had no problems, so I'm not that suspect of this, but your right, it's something that cant be ruled out, will look into this

kasbatts · Nov 23, 2014

sfdon said:
Was the center bearing installed backwards? They are asymmetric.

Mmmm? interesting thought, pretty sure its right, I did put the new one on the same way the old one came off, but that doesn't mean the guy before me got it right.

What way is correct? open side of the rubber diaphragm to the front or back?

and what is the official figure for the pre load? is it 2mm?

kasbatts · Nov 23, 2014

Ian C said:
Steve, when the diff mount cracks through a bolt hole,( usually rear right ) it allows the diff to flop around and can feel like clutch judder. Coupkings website has some good info on this problem. I hope thats not it because it is a pain to repair. Ian.

Will check this out, but i'm pretty sure it's good

Thanks

kasbatts · Nov 23, 2014

Honolulu said:
Were it me I'd jack up the back wheels, run the car in first gear at idle (wheels spinning) and climb under to have a look.

But that could be really really dangerous, so I didn't say it, any impression that I did or might have is certainly erroneous, and I won't do it again.

Recently helped a pal sort his salvage title (engine fire) Tacoma pickup with came with a dented driveshaft (wobbles at speed) and a bent left rear axle (judder in brakes, unstable braking, really bad juju, sent him into the median for mucho bodywork). We jacked it up, ran the truck at idle, got under to discover the dented driveshaft, later stood alonside the spinning rear wheels to discover the bent axle.

Drive shaft is good, it's just come back from a full rebuild with new uni joint and balance, after the shudder goes the car is fine, dives along with no problem and is smooth.

kasbatts · Nov 23, 2014

Stevehose said:
Because the symptom is 1st gear from standing start, something is torquing from the mass of the car. Once moving, not enough force present to cause the problem. So I think some mount or bearing along the driveline is slightly shuddering under heavy load.

Yep, I think your onto it Steve, these are my thoughts as well.

Im going to check the center bearing again, my gut feeling is this is the problem

kasbatts · Nov 23, 2014

lloyd said:
Agree that so-called shudder is most often caused by worn center support bearing and/or disintegrating or severely worn guibo. Since you have evidently eliminated these items from your checklist, you could have a loose, worn or broken motor mount and/or transmission mount. As unlikely as it may seem, the subframe upon which the engine mount is bolted (nearest the steering gear assembly) could fatigue and crack under severe duty. I mention this only because I recall seeing that area of the frame gusseted on an E9 track car with the explanation that it was "a necessary ounce of prevention."

Transmission cross member mounts are notorious for looking fine although in actuality, the mount is severed in two. Alternatively, the mount can be putty-soft, and practically useless. I suppose if a little unwanted grease or oil made its way onto the clutch surface, clutch engagement may not be as smooth as it could be.

http://www.e9coupe.com/forum/showthread.php?t=14861

http://blog.bavauto.com/14153/bmw-v...ile-accelerating-center-bearing-or-flex-disc/

Hi Lloyd,

Gearbox mounts are brand new so they are of the list, the engine mounts however are not, so I might just change these as a matter of course to rule them out, will check the sub frame when I do these

Thanks

sfdon · Nov 23, 2014

It's counter intuitive - open goes towards the front.
Let me know if want a pic.

kasbatts · Nov 23, 2014

sfdon said:
It's counter intuitive - open goes towards the front.
Let me know if want a pic.

Thanks, Will check tonight

Driveline shudder

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