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Discussion Starter #1
Hello,

I have a 1982 Spider in great shape (after a few years of loving care...)

I started hearing a light chatter coming from the transmission... the noise goes away with the clutch depressed. I read on an Alfa book that it is an indication of an input shaft bearing going bad...(or bad).. car has ~140K miles.
Now... the car seems to drive and shift just fine, and the noise is just noticeable because I know every single noise on that car!!

Does anybody has had a similar experience?
Should I start the transmission rebuild process right away or wait until... louder noise...??...

For sure the project would ground my baby for months.. and I know since I have the trany out I would possibly do all work that is suggested...

Thanks in advance for any suggestion.

Giuseppe
 

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Sounds like the 'throw out' bearing and really doesn't need attention if all else is working well. Your right, once you get into it, you should do it all. This was pretty common with my old English cars but has not been much of an issue with the Alfa. I know this answer doesn't really solve your problem and I think we all understand the "know every sound" deal.
 

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Probably throwout bearing. Drive it until the noise scares you and then fix it. A new one can make noises--
 

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But Mad North-Northwest
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Also if either of the rubber boots at the top of the transmission tower tear you can get an amazing amount of gear noise in the cabin.
 

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Discussion Starter #5
Thanks everybody ( and also thank you to my friend Bianchi1 since he said throw out bearing from the get go :) )... what 'threw me' for a spin is the Alfa book [Alfa Romeo all-alloy twin cam companion 1954-1994, Pat Braden] that on the quick checks tips says that "if the transmission noise goes away with the clutch depressed (probably) the input shaft bearing is bad".. and if the noise happens with the clutch depressed then the problem is the throw out bearing....

Go figure.... I think I am just driving it at least until the rains start or the noise becomes much more noticeable...then I start from the throw out bearing, which I did replace with the clutch 2 years ago so it must have no more than 3000 miles...

Thank you
 

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Thanks everybody ( and also thank you to my friend Bianchi1 since he said throw out bearing from the get go :) )... what 'threw me' for a spin is the Alfa book [Alfa Romeo all-alloy twin cam companion 1954-1994, Pat Braden] that on the quick checks tips says that "if the transmission noise goes away with the clutch depressed (probably) the input shaft bearing is bad".. and if the noise happens with the clutch depressed then the problem is the throw out bearing....

Go figure.... I think I am just driving it at least until the rains start or the noise becomes much more noticeable...then I start from the throw out bearing, which I did replace with the clutch 2 years ago so it must have no more than 3000 miles...

Thank you
with all due respect and assuming i am reading correctly, i think you have it backwatds and your book is correct. with the clutch released ( foot off it )
the throw out bearing does nothing... it sits there and does not spin at all and if thats when your noise is occuring then it is one of the primary bearings in in the gbox itself , most likely the input shaft bearing.

if the noise occurs when you put your foot ON the clutch then it could be the throw out bearing because at that point, nothing in the gbox is turning...

if the noise goes AWAY when your foot is on the clutch then that effectively makes certain its a gbox bearing becuase the gbox has STOPPED spinning.

throw out bearing failures are extremely rare. i always replaced them when doing clutches because you are already there and they were cheap but out of , probably a 500 clutches or more i changed in my career, i probably saw only a couple that were actually bad. think about it... its only in service when your foot is on it. how often is that in hours relative to the total hours you put on everything else ?
 

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Discussion Starter #7
Yep English is my second language :) this is a 'foot-off' noise, so as you pointed out so well, it must be the gear box making the noise... and I hope it is the input-shaft...

Grazie
Giuseppe
 

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Trained (ex)Professional, , 1953-2018 RIP,
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Alfa switched to a 'constant contact' type clutch in 1970. What this means is that the release bearing (aka throw out bearing) is in constant contact with the pressure plate. So if the engine is turning, so is the bearing.
Try this simple test. With the engine running and the noise present, put light pressure on the clutch pedal (push it down maybe 1-2cm). This loads the bearing without releasing the clutch. If the noise is still there, the odds on favorite for the 'problem' is the shift boots previously mentioned by Tom. The boots also act as sound insulators helping to keep normal gearbox sounds from entering the cabin.
 

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Alfa switched to a 'constant contact' type clutch in 1970. What this means is that the release bearing (aka throw out bearing) is in constant contact with the pressure plate. So if the engine is turning, so is the bearing.
Try this simple test. With the engine running and the noise present, put light pressure on the clutch pedal (push it down maybe 1-2cm). This loads the bearing without releasing the clutch. If the noise is still there, the odds on favorite for the 'problem' is the shift boots previously mentioned by Tom. The boots also act as sound insulators helping to keep normal gearbox sounds from entering the cabin.

i presume you are talking about the residual hydraulic pressure from gravity keeping the arm forward. while true , it is a " no load " condition and the same as every other hydraulic clutch that doesn't have a mechanical adjustment. i've never seen one of those fail or make noise ever. its possible of course but it seems very unlikely to me.
 

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Trained (ex)Professional, , 1953-2018 RIP,
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i presume you are talking about the residual hydraulic pressure from gravity keeping the arm forward.
No. Not from gravity.
The non-adjustable pushrod slave cylinders in the constant contact type clutch system (called the Type 3 clutch by Alfa) have a spring loaded piston. The spring pushes the piston in the same direction as the hydraulic pressure does. So the spring pushes on the piston which in turn provides enough hydraulic pressure to keep the release bearing in constant contact, and spinning with, the pressure plate.
 

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My clutch rattles when the motor is idling and it is due to the friction plate being a bit loose on the splines. I have learned to ignore it.
 

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with all due respect and assuming i am reading correctly, i think you have it backwatds and your book is correct. with the clutch released ( foot off it )
the throw out bearing does nothing... it sits there and does not spin at all and if thats when your noise is occuring then it is one of the primary bearings in in the gbox itself , most likely the input shaft bearing.

if the noise occurs when you put your foot ON the clutch then it could be the throw out bearing because at that point, nothing in the gbox is turning...

if the noise goes AWAY when your foot is on the clutch then that effectively makes certain its a gbox bearing becuase the gbox has STOPPED spinning.

throw out bearing failures are extremely rare. i always replaced them when doing clutches because you are already there and they were cheap but out of , probably a 500 clutches or more i changed in my career, i probably saw only a couple that were actually bad. think about it... its only in service when your foot is on it. how often is that in hours relative to the total hours you put on everything else ?

Steve's right.

The noise you hear is the input shaft bearing. If you wait to long it will chew up the inside of the bell housing to were you will need to find another one. I had one years ago that the owner kept driving and when the bearing broke apart it also took out the case halves along with the bell housing.
 

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No. Not from gravity.
The non-adjustable pushrod slave cylinders in the constant contact type clutch system (called the Type 3 clutch by Alfa) have a spring loaded piston. The spring pushes the piston in the same direction as the hydraulic pressure does. So the spring pushes on the piston which in turn provides enough hydraulic pressure to keep the release bearing in constant contact, and spinning with, the pressure plate.
i have to respectfully disagree. that spring you are talking about is to keep the piston in contact with the actuating rod so that vibration or g forces don't retract the piston leaving a " no clutch " condition the first time you hit the pedal there after and require you to pump the pedal to get a clutch again. it provides an unfintesimaly small and meaningless force on the TOB. technically, i suppose , you could say the TOB is " against " the PP but it is in a completely no load cndition. you may as well have it in your coat pocket for as much wear as it sees or noise it will make when the clutch isn't dperessed.
 

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My initial post was to address the following incorrect statement (and to offer a simple diagnostic procedure.
...with the clutch released ( foot off it )
the throw out bearing does nothing... it sits there and does not spin at all...
After I explained how the constant contact Type 3 clutch works, you state;
...technically, i suppose , you could say the TOB is " against " the PP but it is in a completely no load cndition.
which is exactly correct and confirms what I previously wrote, "If the engine is turning, so is the bearing." And the following quote implies a no-load condition with clutch pedal released;
...put light pressure on the clutch pedal (push it down maybe 1-2cm). This loads the bearing...
Alfa Romeo published a document in 1970 which describes the Type 1, Type 2 and Type 3 clutches. If anyone would like a copy, please drop me a PM and I'd be happy to send it.
 

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Richard Jemison
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chatter

My clutch rattles when the motor is idling and it is due to the friction plate being a bit loose on the splines. I have learned to ignore it.
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Ed is correct, and his is a light no torque spring clutch disk.

The stock ones have the same issues and additionally the "torque'' springs in their cages get loose with use, causing more rattling noises.

I suggest you listen for the noise with the clutch engaged (in neutral) with your foot both lightly on and off the clutch petal to lightly load the release bearing. If the noise stops when light pressure is applied, then, yes there is a TO bearing issue. If it continues then it is a clutch disk issue. Either splines or springs. Neither of these warrant dropping the transmission, unless it`s just absolutely time to change the clutch disk due to milage on it..

I wouldn`t give the input shaft bearing another thought. It can`t damage anything and if it was bad there would be a lot of growling from the trans and shifting issues between 3rd and 4th.

If the noise is comming from the shift tower, then likely the seal at the top of the cover disk has died, or the shifter mechanism inside needs more tension on the belview washer.

In that case, just push down hard on the rubber covers and load the sliding covers.
 
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