Clitiky-clank noise from transaxle - Page 2 - Alfa Romeo Bulletin Board & Forums

Reply
 
LinkBack Thread Tools Display Modes
post #16 of 50 (permalink) Old 10-31-2015, 12:04 PM
Registered User
 
Join Date: Oct 2015
Posts: 10
Noted. The car had been worked on shortly before I bought it so everything was tight along the shaft. The vibration appeared after the rear giubo had been swapped and the previous owner was unable to get the workshop to rectify it. We looked at the centre bearing and replaced it before the shaft was balanced. The clutch angle is interesting. The replacement gearbox has the old clutch from my car on it but the noise has gone, suggesting that the problem was further along the input shaft. I have not split either gearbox to look inside so am not sure what the difference is.
MFindlay is offline  
Sponsored Links
Advertisement
 
post #17 of 50 (permalink) Old 10-31-2015, 02:14 PM
Registered User
Gold Subscriber
 
Join Date: Dec 2006
Location: 592 Browns Trace Jericho, Vermont
Posts: 2,257
Garage
I'm telling you the yoke in the middle is loose! Not the one on the end!! Raising the idle only hides this problem. The noise on my Fetta as well only occured at Idle Sounded like someone was hitting my drive shaft from underneath with a hammer. They forgot to tighten the NUT!

AlfasRule!

1972 Montreal (The Pumpkin)
1975 Alfetta Sedan
1975 Alfetta Coupe Race Car
1982 Spider
1984 GTV-6
1984 GTV-6 Verde (GiGi)
1987 Milano (Da NEW Winta Beata)
1987 Milano Verde(Da kREDden Mobile)

Last edited by alfasrule; 10-31-2015 at 02:20 PM.
alfasrule is offline  
post #18 of 50 (permalink) Old 10-31-2015, 02:41 PM
But Mad North-Northwest
Platinum Subscriber
 
Gubi's Avatar
 
Join Date: Sep 2003
Location: SF Bay Area, CA
Posts: 8,400
Quote:
Originally Posted by sportiva View Post
It's the clutch disk damper springs shuddering at low idle. it is not the gear set.
The gear set is "constant mesh" and any backlash sounds are muted by the gear oil, usually the only sound you hear from inside the transaxle are the dog teeth crunching when the synchros are wearing
Clutch springs can make a similar noise, but constant mesh gears can rattle as well. Just do a web search for "neutral rollover noise" and you'll find plenty of examples and technical write-ups of the phenomenon.

In my case at first I thought it was the clutch as well. But when the clutch went and I replaced it with a new complete assembly the noise was exactly the same. So pretty sure it's in the box, but either way it's not anything to be concerned about.

Anyway, if you can make the noise go away by pushing in the clutch pedal then it probably isn't the pinch bolt or yoke or anything forward of the clutch input.

I think I said all of this three months ago

Tom

1991 Spider
1963 Giulia Spider (1750 engine)
Gubi is online now  
 
post #19 of 50 (permalink) Old 10-31-2015, 03:31 PM
Registered User
 
Join Date: Oct 2015
Posts: 10
I am relating my experience and every car is different. There was a combination of incorrect parts, wear and poor fitting in my car that produced a syndrome. It was not limited to one fault. An old Alfa owning friend has recently sold a 75 with a high milage and an untouched drive shaft as smooth as a new one. The take home lesson for me is find out what the correct specification is for your car and return everything that you practically can to that.
MFindlay is offline  
post #20 of 50 (permalink) Old 10-31-2015, 06:53 PM
Registered User
 
sportiva's Avatar
 
Join Date: Aug 2005
Location: Newcastle Australia
Posts: 339
Not in an alfa transaxle nothing in there will resonate that type of sound outside the casing at idle.
The oil bath dampens any rattle or clatter, the intermediate flange or layshaft bearings would have to be completely knackered or the lay or mainshaft nuts would have to be loose anyway any sound from that area would not resonate,
it would be a dull thuddy sound
I would get a stethoscope or large screwdriver and listen along the drive line near the gear set area of the transaxle, clutch housing,center bearing middle yoke and the bell housing near the front yoke. and it goes without saying
DONT TOUCH ANY ROTATING PARTS


cheers
sportiva is online now  
post #21 of 50 (permalink) Old 10-31-2015, 07:37 PM
But Mad North-Northwest
Platinum Subscriber
 
Gubi's Avatar
 
Join Date: Sep 2003
Location: SF Bay Area, CA
Posts: 8,400
Not sure why you think the front of the Alfa transaxle is different from any other manual transmission...I mean, that's just not true. Manual boxes all pretty much work the same and some of them can rattle. Here's a good write up of the problem and how to diagnose vs. other issues: http://www.tccoa.com/articles/mn12ho...Diag-noise.pdf

(Note that that's for a Thunderbird, but the design is pretty much the same as the Alfa transmission [constant mesh gears and oil bath and all, less the Porsche-style synchros]. Diagram here if you're curious: http://www.manualtransmissionpart.co.../m5r2-2012.pdf)

Anyway, the much easier way to test all those driveshaft parts in front is that I push down the clutch pedal and hear the noise gradually wind down. Pretty sure that rules out everything in front of the clutch! Beyond that, I'm sure it isn't bearings. They whine, and the noise would get worse under load, not happen only at neutral. It's not the clutch because I replaced that assembly with no change, and also it only happens when the transmission gets hot and the fluid gets thin which also rules out the clutch.

So, we've got a rattling noise that only happens at hot idle, goes away when you push the clutch in, and goes away as you slightly up the revs. That's neutral rollover noise: can't be anything else. Other sets of symptoms may have other causes, but for the OP and I this is the issue.

Did this for, oh, 40K miles or so without getting any worse (S-cams idle a bit lumpy which was the source of the issue). Upping the idle a touch pretty much fixed it when it finally got on my nerves.

Tom

1991 Spider
1963 Giulia Spider (1750 engine)

Last edited by Gubi; 10-31-2015 at 07:53 PM.
Gubi is online now  
post #22 of 50 (permalink) Old 10-31-2015, 09:03 PM
Registered User
 
sportiva's Avatar
 
Join Date: Aug 2005
Location: Newcastle Australia
Posts: 339
I agree that raising the idle will help, it's proven and peer reviewed. I don't accept its neutral rollover, the alfa transaxle is different
the alfa transaxle mainshaft and secondary shaft are supported in the middle at the intermediate flange by a 2 row roller bearings and the mainshaft is also supported at the back near the diff by a huge needle roller bearing , not on bearings either end like nearly most other transmissions.
Reverse and 5th are before the flange 1st 2nd 3rd and 4th are after. It is a very tight and compact design the only parts that have movement that will induce clicking sounds are the synchro rings and the quadrants inside he synchro unit and to a lesser extent the synchro hub outside of the unit ..........and the oil bath will silence them
It is a sound that is annoying and sometimes embarrassing and lucky for us goes away when we drive off


cheers

Last edited by sportiva; 10-31-2015 at 09:24 PM.
sportiva is online now  
post #23 of 50 (permalink) Old 10-31-2015, 09:46 PM
Registered User
 
Join Date: Oct 2015
Posts: 10
The sound I had in the original gearbox was noticeable at idle but became louder when changing gear, producing a noticeable growl when spinning down. I would not describe it as clickety clacking, however, more of a rumble. It did sound like a gear meshing issue rather than a bearing failure but only forensic examination of the insides could produce the necessary evidence. It changed gear well and had no synchro problems. And it did have oil in it.
MFindlay is offline  
post #24 of 50 (permalink) Old 11-01-2015, 12:14 AM
Registered User
 
sportiva's Avatar
 
Join Date: Aug 2005
Location: Newcastle Australia
Posts: 339
I would have liked to have done an autopsy on that gearset, transaxles are my favorite fix. Your noises could have been many things with those symptoms . I have seen pinion height shims wear down to paper thin this allows the gears and the main shaft to move back and forward in the space the shim used to occupy with all sorts of rumbles and whining sounds.
the alfa transaxle is fine for a road car it's only shows it's weakness when raced or when high horsepower is put through it. If they are used with a little care and sympathy they will go for years without problems

cheers
sportiva is online now  
post #25 of 50 (permalink) Old 11-09-2015, 03:29 PM
Registered User
 
Join Date: Oct 2004
Posts: 891
My GTV-6 had that same noise when I owned it back in the 80's. It turned out to be a metal cup washer that was on the driveshaft itself if I remember correctly. It was loose and would rattle around at low speed. Wish I could remember the exact location but if you crawl underneath physically inspect the different ends you should be able to find it.

chuck
6alfas is offline  
post #26 of 50 (permalink) Old 11-09-2015, 08:08 PM
Richard Jemison
Platinum Subscriber
 
Alfar7's Avatar
 
Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 5,820
Noise

Once the splines on the clutch shaft have worn and have play between the clutch disk splines then changing the clutch or clutch disk will not make a difference.
On these cars the 3 rubber guibos exagerate the power pulsed between the front and rear flywheel (that contain the clutch disk) and its going to rattle back and forth at idle until the revs smooth out at the rear flywheel.

Richard Jemison
RJR Racing

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"When you are dead you don`t know it.
Only those around you are distressed.
Same with stupid"
Alfar7 is offline  
post #27 of 50 (permalink) Old 11-10-2015, 01:26 AM
Registered User
 
Join Date: Oct 2015
Posts: 10
I think I have a grasp of the physics of it now and it is a salutary lesson about not attempting to improve the original factory setup unless you are aiming to re-engineer the whole thing. I agree that getting the firing impulses even at idle makes a big difference and the balance problems arise in the giubos rather than the shaft itself. Balancing the shaft made absolutely no difference which was frustrating to say the least. The problem was only apparent with the shaft fitted up in the car even though it ran perfectly true in the lathe.
.
MFindlay is offline  
post #28 of 50 (permalink) Old 11-12-2015, 03:17 PM
Registered User
 
Join Date: Jul 2009
Location: Arlington, Virginia USA
Posts: 164
I've watched this thread for awhile, so far I've avoided my usual preface but here goes: I've driven and owned my GTV6 for almost 30 years - I can't remember when it didn't rattle a bit at idle, especially when hot, after a long run etc. Never had a problem with the drive line in almost 200k miles. Replaced a guibo or two, center suspension bearing. Clutch has about 110K miles on it. If anyone remarks on te noise rev the motor, no one will hear it. Its definitely not a part going bad or something that will break the car.

Ciao
8oclock
8oclock is offline  
post #29 of 50 (permalink) Old 11-13-2015, 01:24 PM
Registered User
 
ToonRboy's Avatar
 
Join Date: Jan 2007
Location: Illinois
Posts: 2,248
Send a message via Yahoo to ToonRboy Send a message via Skype™ to ToonRboy
To the original poster Trooper, thanks for posting this issue. I think the title is very descriptive as well as that sound describes neutral rollover very well (which besides clickety-clak, has been described as a couple marbles in a coffee can). Anyway, these V6's do not have a harmonic balancer integrated into the crank pulley. It has a two piece drive shaft connected to the crank spinning at crank speed. Those rubber Giubos are the only thing providing for harmonic absorption - when the motor is disconnected from the trans (plus there's the mass of the 2nd flywheel back there that also helps). While connected, there are the springs in the clutch disk/s as well. That's it! So in my mind only a couple/three things are happening.

a. Something loose in the clutch so that springs can't do their job. Alfar7 mentioned splines worn or maybe the clutch springs themselves.
b. Driveshaft loose so that giubos are vibrating along with the shaft as one, rather than absorbing vibrations. Yoke connections etc.
c. Harmonics so bad that both giubos and clutch are unable to cope.

Third one would attest to state of tune, engine mounts to include bellhousing one. Perhaps front trans mounts. The fact that simply raising the idle a few hundred rpm to serious positive effect tell you a little something (uh, say "I don't think so" to the trans rebuild?).

Interesting to note that both Trooper and another had mentioned new clutch, and in Troopers case also new Giubos, so as the attached article says, can be an elusive issue to fix!
Attached Images
File Type: pdf Diag-noise manual trans.pdf (143.3 KB, 68 views)

Last edited by ToonRboy; 11-13-2015 at 01:42 PM.
ToonRboy is offline  
post #30 of 50 (permalink) Old 11-13-2015, 02:05 PM
Del
Senior Member
Gold Subscriber
 
Join Date: May 2005
Location: seattle
Posts: 11,888
Every transaxle equipped Alfetta, GTV6, and even the Milano (but not much in comparison) we've owned has had this rattle, and when I first commented on it to Carlo, he said that Alfa said it was the transaxle internal gear train making the noise due to neutral roll-over. inherent in the design of the transaxle drivetrain.

He said live with it.

Del

Seattle

89 Milano (wife's daily driver since 1989, Shankle Sport)
91 164S (my daily driver since 1994)
94 164LS (~Q) (trip Alfa since 2000)
72 Morgan 27 (water time since 1976)

previously owned since 1964:

62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6
Del is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
Replace with
For the best viewing experience please update your browser to Google Chrome