11- Driveshaft

• Unusual vib
• Doughnuts
• Driveshaft FAQ
• Bottom end rattle
• Center bearing change
• Vibrations
• Strange noises
• Fast donut usage
• more vibes
• Length adjustment

j.h.bouma@wb.utwente.nl writes:
<<  I thought I did
 everything right to prevent driveline balance problems by buying the
 complete unit, but the first test drive showed vibrations around 2800rpm.
 Much bad language ensued. >>
Jaap,

Two possibilities.
First, did you loosen the lock bolt on the front donut spider and let the 
shaft find its proper length?
Second, are you sure you put the blocks between the chassis and deDion back

correctly?
Hope this helps, good luck,
John Katos

Thanks to Ben, Bernie, Paul, Brian, Darren, Dan and Tom for their responses
to my rear donut query. Most responders politely questioned the quality of
my installation but as the old and very broken donut came off the car with
the same "wave set" I've added to the new one I reckon my instal was as
good
as the pros. All the little tangs are in all the little sockets etc.
It now seems that some distortion is a feature, not in my view a very
desirable one. Paul Irvines neat driveshaft overhaul instruction on his
webpage shows a sectioned view of all three couplings, for the GTV6 I
think,
and the diagram for the rear coupling shows what I think is a pretty bent
donut!

http://www.crl.com/~pi/project/tech/driveline/donuts.htm

Regards, Lee

Thanks to all who responded to my query about my Milano's bottom end rattle,
most of you advised of a driveshaft problem, but the winner of this diagnosis is
Doug Sedon who accurately diagnosed it as the Clutch Throwout bearing.
While the donuts have some surface cracks and the support is a tad worn, up on a
lift you can clearly hear the noise coming from the clutch assembly, stepping on
the clutch makes it go away. I was advised to do nothing as the clutch is
only 20 K miles old.

Date: Thu, 2 Mar 2000 12:34:19 -0700 (MST)
From: Marcantonio Sandro <Sandro.Marcantonio@Colorado.EDU>
Subject: Bottom end rattle on milano
In fact, the bottom end rattle that goes away when the clutch is depressed
is a small bearing in the drivesaft center coupling.  When you press on
the clutch you actually quiet the rattle by decreasing the length of the
driveshaft very very little.

Joel Hailey from centerline gave me this tip. Be careful replacing this
bearing, if you do it wrong your driveshaft will vibrate like a bad
dream.\\\

Sandro Marcantonio

> Thanks for your prompt reply Willy. I have taken your suggestion on
> board but before I delve to far into that area, there is a  symptom 
that
> doesn't seem to fit . That is that it only occurs whilst driving and
> applying torque to the transmission. It cannot be heard whilst 
revving
> with the car stationary. I would be most appreciative to hear of any
> other ideas.
> 
> 
> [Non-text portions of this message have been removed]
Hey, I know this noise.
I had the very same symptoms on my old Turbo.
I also had the exhaust removed and had the donuts replaced, but no 
luck.
Finally, I sold the car but kept contact with the new owner and after 
a while he told me that this noise also got on his nerves and took 
the car to a mechanic (different than mine), who told him that it was 
(I don't know the technical slang in english, so i will try to 
describe it to you) somewhere between the flywheel and the "turtle"?, 
the aluminium thing that bolts on the engine block and houses the 
front donut. From his explanation I figured out that it is some kind 
of bearing that needs relacement.
I'll try to get more specific info and pass it on to you soon.
Thank God it has not appeared yet on my 3.0 V6.

I hope I can help you since I know myself how nerve-breaking it is.

Take care,

Danny
Thessaloniki, Greece

Many thanks Danny for your input on "The NOISE".  I'm sure I know which
bearing you are referring to.  The front Donut is inside the aluminium
Bell Housing and inside the Donut  is what is called a Spigot Bush which
fits into the centre of the flywheel.This keeps the tailshaft centred
exactly so that it does not vibrate. There are also similar ones on the
centre and rear donuts.
When I replaced the front Donut I visually inspected that particular
bush and it did not seem to have any visible wear but I did not measure
it precisely for abnormal clearance. It certainly sounds like that is
where the noise is originating. (or maybe at the centre donut)
Before I pull the tailshaft out again I would be very pleased if you
could find out if the new owner of your car did actually get the noise
eliminated and if that is what caused it. It is driving me nuts.

Thanks again

Jim

G'day Mikko

Could you please read my notes "THE NOISE"  part 1 and part 2   4th
April and see if you think there is any similarity to your noise. As you
will see I have changed the centre bearing which on inspection sounded a
bit worn but this did not cure my noise problem. The replacement bearing
is an SKF 6205-2RS (or equivalent) and costs $12 Australian provided you
purchase it from a bearing company and not an Alfa dealer. There are
some very good instructions on
http://reality.sgi.com/sikand_mti/clone/drvshft.html .
Whilst you are doing this you can inspect your donuts ($A150.00 each)
and if there is no sign of cracks in the rubber there is no need to
change them. I would be happy to give you more information if you
require it.

Good luck
Jim

Hi all,

A wise sage once told me that low speed vibrations on a GTV/6 are to 
do with the front of the drive shaft, such as bad motor mounts or 
broken front donut. He also said that high speed vibrations are to do 
with the back end of the car, such as a bad rear donut, transaxle 
mounts or unbalanced clutch.

Note that if the clutch has been replaced, or the rear donut removed 
for any reason, the nuts and bolts MUST be replaced in thier original 
positons and the alignment of the shaft to the clutch must be 
maintained, as the propshaft is balanced in the factory, on the car 
including all the nuts, bolts, donuts, clutch and everything.

Dunno if this true, or not, and I can't remember who the sage was 
now. Seemed reasonable at the time.

By the way, a 24v V6 from a 164 will fit in a 2.0 TS 75, but you need 
to replace the oilsump, and maybe do some drilling ... I have seen 
one, and it looks cool. Of course the mechanical bit is easy, it's 
all the wiring stuff that will take ages...

Regards, Jim Chase
1989 75 3.0 (dead clutch)
1972 Montreal ( trailing arms have left the building...)

G'day Alex
I have had a noise that sounded exactly like what you described. I have
been trying in vain to find another noise which I have enquired
extensively about without resolving it, when this other noise like yours
sprung up. It was a very loud high pitched screaching noise which only
occured at certain times and when I found it I was amazed that that such
a simple thing could make so much noise.
It turned out to be a broken off exhaust hanger bracket on the support
frame that is bolted to the car underneath the tailshaft centre bearing.
The broken off piece of the exhaust hanger bracket was still held
roughly in place by the rubber hanger and under certain conditions would
cause a high frequency vibration against the other half of the broken
bracket. It was very loud and tricky to find because with the broken
half still being held in place it was only when I shook the exhaust by a
large amount that I saw it moving.
If this is your problem the good part is that it is easy to fix.
Good luck

Jim

Date: Mon, 11 Dec 2000 09:51:48 EST
From: JJK1204@aol.com
Subject: Re: gtwe6 driveline giubos

In a message dated 12/10/00 9:58:50 PM Central Standard Time, 
dsedon@netscape.net writes:
 

> hi all,
> 
> if brand-gnu giubos blow-out in 6 months, then either the drive-line is 
> outta
> balance, or yer doin' drag-race-type starts, or, ya got a defective giubo.
> 

Add to this option four. Driveline out of alignment. I was going through 
donuts faster than Police Chief Wiggems. First when everything is assembled 
loosen the locking clamp on the driveshaft spline located by the front donut. 
First be sure that the driveshaft is properly oriented with the rest of the 
driveline, either on the ground if you are really skinny or supported on the 
rear wheels or Dedion if you need the clearance as I do. DO NOT SUPPORT THE BODY as this lets the Dedion drop and lengthens the driveshaft. Idle the 
engine so that the shaft finds it's correct length. Tighten the locking bolt. 
I also do not tighten the cat to exhaust manifold connection until everything 
else in the exhaust system is tight. I do this since I noticed that to get 
the cat middle section together that I was tilting the engine in order to 
align it correctly. Using these two methods got rid of my donut blowing 
vibrations.

John Katos
West Dundee, IL

Taking a stab at the cracked bell housing on the spider: 

Growing up in Portland, Oregon, I spent many an afternoon getting parts
and advice from David Rugh (Rugh
Engineering). I remember him showing me the cause of a chronic bell
housing failure - the output shaft of the
transmission. 

Initial syptoms were loose fasteners between the bell housing and the
engine. After double nutting these, I
pretty sure the next symptom was cracking of the bell housing. 

Anyway, the root cause was that the output shaft on the transmission. It
has a ball on it. This ball allows the
donut to be centered while the short part of the driveline and the
transmission fall out of alignment (axial
alignment). The short shaft has a hard steel "socket" pressed into it
which is filled with grease and protected
with a lip seal. After the grease goes away, the "socket" wears a flat
spot on the ball end of the shaft (which is
soft) and consequently sets up a vibration that leads to cracking and
loose fasteners. Dave had found a way
to fix the shafts and harden the area to give better life. 

For most of use, the fix requires a new mainshaft (output section) for
the transmission. Better yet, just buy a
used transmission (with a good end!) and when you install it, make sure
that this "socket" is greased and
SEALED. 

Thats my guess. 

For those with Milanos or GTV-6's the ball end detail can be found at
the input shaft of the transaxle. Same
function, centers the donut. This one also has a lip seal and should be
greased. The engine donut also has a
centering feature (slightly different design) which is greased and
sealed. If your front donut fails, you should
replace this seal also and regrease. Else the car may never be as smooth
as when Alfa shipped it out. 

Erik Roe
Alfa Romeo Owners of Oregon 

In a message dated 6/27/2001 4:28:43 PM Central Daylight Time, 
schugof@yahoo.com writes:
 

> .  I am aware that the front section has its connection into the crankshaft 
> on a spline on the driveshaft allowing it to be moved (It appears such is 
> only for assembly of such connection and not for length adjustment.).

No, it is for length adjustment. Loosen the locking bolt enough that the 
spline is loose but not too much so the bolt comes out. Run the car at
idle for a minute and then tighten the bolt. Be aware you might have
destroyed the rear donut. Also be sure that when putting the exhaust back on that you do not force the engine to tilt. The best way I found to do this is to
assemble everyhting loosely and then tighten back to front leaving the cat pipr
to manifold for last.

John Katos
West Dundee, IL USA