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Discussion Starter #1
I have a '74 2000 GTV and it has a clunk in the drivetrain. I thought it was a universal joint - sounds a bit like someone tapping the driveshaft with a hammer. The driveshaft is now rebuilt and the clunk remains. Have traced it to the rear axle and it seems to be related to takeup in the diff. It has a limited slip diff and someone has suggested its normal - anyone know more about diff clunks in LSDs?
 

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Hi,

I'm no expert but it would help those of us who are if you give more details of the problem. It shouldn't be normal unless it is a tight LSD but this doesn't sound like your issue.

Is it only when you move off from standstill, or maybe brake?
Is it only when you turn hard?
Is it there all the time?
Really loud so your head hurts or just barely noticeable?
Is it a regular sound (steady or faster with speed) or only happens every now and again?

I'm sure you'll get your answers. There are plenty of Alfa doctors on here but you need to give them your symptoms.
 

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I have the same issue and will be interested to see what the problem actually is, I have replaced my prop bearing support, my universal Joint and the issue still persists and I don't have an LSD by the way.
 

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I have a '74 2000 GTV and it has a clunk in the drivetrain. I thought it was a universal joint - sounds a bit like someone tapping the driveshaft with a hammer. The driveshaft is now rebuilt and the clunk remains. Have traced it to the rear axle and it seems to be related to takeup in the diff. It has a limited slip diff and someone has suggested its normal - anyone know more about diff clunks in LSDs?
Normal, no. Common, yes. Does it clunk as you let out the clutch from standstill and when applying throttle after gearchange?
If so, I would suspect diff pinion backlash.
 

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Discussion Starter #6
Thanks - in answer to the questions for more info - it is most noticeable when I am taking off from a standing start or don't let the clutch out smoothly after a gear change. the other time it happens is if i throttle off suddenly - it seems most noticeable at lower speeds.

It is not deafening, but it is quite clearly audible

Cheers
 

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Discussion Starter #7
Normal, no. Common, yes. Does it clunk as you let out the clutch from standstill and when applying throttle after gearchange?
If so, I would suspect diff pinion backlash.
Thanks Big D - sounds like that is it - excuse my ignorance but if that is the problem - what would be required to fix it?

Cheers
 

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Forgot to ask if it made the clunk when you backed off the throttle, and it does. Sounds like that is your problem. You'll need to find someone who can adjust the backlash. Might be lucky and be able to reset the preload on the bearing, maybe not. Either way you need someone who is familiar with these diffs and can set them up properly.
If it makes you feel any better, I've heard these making a very noticeable clunk and still go for years.
Good luck.
 

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Discussion Starter #9
Thanks Big D - encouraging to know that it might keep going - I don't fancy having the diff lock up!!.
 

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Threealfas, I didn't mean to exclude the Aussies!
Mick, when you had the driveshaft on the bench, did you look at the front of the driveshaft where it mates to the g'box?
As years go by, the driveshaft, in this area, can take a flogging.
Cheers and hope you sort it out.
Ian
 

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Discussion Starter #13
Hi Kiwi Kid - i didnt check the front end - had the shaft overhauled by a mechanic. i don't think its at the front end - we've had it on a hoist and seems to be coming from the rear - but it is a different sound with the wheel s off the ground - i think because its not transferring the sound up the driveshaft with the back wheels free. The diff backlash sounds most likely so i'll try to chase that down first.

PS - you're right - it is good to see a couple of kiwis here - oh alright - and an Aussie.
 
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