ALFAGTV6.COM

Well, I've searched the forums and can't find the info I am looking for.

I have a grumbling/growling noise from the rear of the car when in neutral, idling. If I depress the clutch to select a gear, the noise disappears.

Donuts are all new, as is the center bearing. Exhaust is not touching the halfshaft. DeDion fwd bushing is new and well peened in place.

My thinking on this is that when the clutch pedal is not pushed to the floor, the clutch is engaged and there is a large thrust force on the clutch output/gbox input shaft. Could the thrust bearing there be worn?

Or could this be the throw-out bearing? Perhaps when it is not being acted upon by the fork, it sits on the clutch input shaft, idly rattling away.

Any thoughts?

Thanks in advance.

Dave sounds very much like the throw-out bearing to me.How old/miles is your clutch ? You might try spraying some lithium grease into the opening through which the clutch fork protrudes and this will quiet things down temporarily and confirm the source of the noise.

Thanks Murray. That's a great suggestion.

My '6 has ~56,250mi and is an early '85. Twin plate clutch. She may have resided in someone's garage for extended periods of time. Definitely polisher, not mechanic-owned. A lot of work has been done replacing all things rubber; from fuel lines to suspension bushings. Then there was the gbox....HGaskets....t-belt & tensioner.....

I would imagine a bit of lithium grease sprayed on 1 of the clutch plates wouldn't be an issue?

Dave with 56k on your clutch it likely has plenty of life left so if the lubricant reduces the noise you can plan on either living with it (noisy throw-out bearings don't necessarily mean that they are going to fail) or just change the bearing.If any lubricant finds its way onto the clutch plates it will be burned off with a couple of aggressive launches.

Thanks Murray!

On the other hand you can usually really hear the gearbox spinning when you are stationary in neutral with the engine running. A lot of stuff spinninig around in there you know, might be a bad gearbox bearing or even completely normal sound.
Have you got any other transaxle car to compare with?

3 75s and 4 GTV6s Mats. I know 2 of the 75s don't exhibit this much noise. 1 of the other '6s does. It's owned by the son of an (ex)Alfa dealer. He has reported that the noise is very common; nothing to be concerned about.

Keep in mind, the noise disappears when the clutch pedal is pressed in.

What type of bearing is the throw-out? Is it a brass bushing? Or is it a proper roller bearing?

If it is a bushing, what is there to stop it rattling around when there is no thrust force applied? Is there a fastener/clip that holds it to the fork, thereby keeping it axial? My fork socket is quite worn...

It's a proper bearing and it's expensive.
It centers on a piece of pipe over the input shaft.

It's less expensive if its got the OEM dual disc clutch for the GTV6. The single throwout is like 250 or something.

Rob

Wow. Now we're talking serious money.

I'll bet its an SKF or IKO or FAG bearing that is a std part....so many of these parts can be sourced thru non-Alfa suppliers, such as wheel bearings.

Mats/Rob, you don't happen to have a photo, do you? I had a look on the BB and on .org here; alas no luck.

Thanks for the responses guys.

There are three types, the one above, another pull type for single discs (might be the same as double though) and the push type found in the 4 cyl versions.

I'll try to snap a pic of the push type today in the garage.

The one for single disc's is different than the twin disc for sure. And its about 100 bucks more expensive...which seems quite backwards to me.

I'm just redoing the clutch in my GTV6 now...sent it out to performatek for a couple upgrades before installing. Nice idea...can't wait to see how it runs!

Rob

I wonder was the single disc TO brg upgraded to something beefier -> more expensive?

Looking at it from a cost point of view they probably carried over the clutch arm assembly and I'm guessing that the total height of the double clutch assembly is larger and therefore the new single plate bearing is longer to take up the extra space.
They might have realized that there was a problem and beefed it up as well, as a matter of fact it is very likely since the single plate spring must be more powerful to get the required clamping pressure.