[s-cars] drivetrain whir / clatter upon CMG install

[Paul Gailus]

Paulie,

It's possible that torsional vibrations are causing the
rattling noise at the splined connection between the
clutch disc hub and the transmission input shaft.
The OEM clutch disc doesn't have a torsion damper,
but the OEM flywheel does include a torsion damper
between the "dual masses"

If the SPEC clutch disc doesn't have a torsion damper
then this could be another factor contributing to the noise
(over and above the higher level of vibrations that get
through the LWFW).

Paul


----- Original Message -----
From: Krasusky Paul (WQQ2PXK) <WQQ2PXK at ups.com>
To: s-car-list <s-car-list at audifans.com>
Sent: Tuesday, November 04, 2003 7:11 AM
Subject: [s-cars] drivetrain whir / clatter upon CMG install


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> Morning-
>
> Hoping to probe the collective technical minds here (i.e. Igor, Bob(s),
> Keith, Scott TB, Ned, etc.).
>
> After 3 or so weeks, and SPEC sending the wrong clutch (that went in, then
> back out, of the f'n car), my CMG / NEA LWFW / SPEC II hybrid / short &
> weighted shifter / new slave install is complete.  Drives f'n amazingly
> (more on all that another day).
>
> I'm getting some good drivetrain clatter in 2nd-6th gears when the car is
> bogged.  Now I realize some 'whir' is normal due to the aluminum flywheel
/
> absence of dual mass.  But there's a noise at idle that bugs me.  Here's
the
> symptoms:
>
> - At idle, with clutch pedal OUT, the 'whir' that the drivetrain makes (in
> 2nd-6th) can be manipulated by blipping the throttle...  producing a good
> audible clatter.  Sounds like a loose heat shield type sound, but it's
from
> the bellhousing.  Sounds JUST like a throw out bearing 'whir' at idle (yes
> it's new), until it clatters when I hit the gas... no TOB has ever done
that
> to me.
>
> - Whir / clatter go totally away when clutch is depressed... silent.
Comes
> right back when declutch.
>
> - Cannot feel anything 'slapping around' in the bellhousing or tranny, put
> hand on it, don't feel any knocking anywhere
>
> - Nothing appears loose anywhere.
>
> - Drives excellent, no noise as long as there is load on the drivetrain.
> SPEC II not quite at 500 mile break in, skips off line in 1st and reverse
> still (annoying, SPEC says will go away).
>
> The CMG is a Kludge-redone unit, I'd *hope* to rule that out.  I'm
> 'guessing' maybe a loose spring on the clutch disc?  Or something similar?
> Won't know unless I yank it, again...  as much as I like to yank I dread
the
> thought of doing this job "The Mahoney Way" (3x).  Looks like I'll have to
> rope an unsuspecting Rossato into a weekend project this winter.  Yay!
>
> Any thoughts / experiences greatly appreciated.  I have trouble thinking
> "that's the way it's supposed to be"...  maybe the whir 2-6, but not the
> idle clatter...  if it is, it's REAL embarrassing sounding, sounds like a
> POS... no, not a Power Output Stage...
>
> TIA.
>
> -Paul Blackthumb... it's always something
> '95 file://S6 drives like a real MUTHAF'ER at least, thoughts later
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