Help please

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Trevor

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Alright guys, im looking for some help here. Im gonna lay out as much info as i possibly can to try and address most questions that would be asked. Bought this sandcar a few months ago, thought i heard something in the trans but wasnt really sure, so i opted to just have it gone through for piece of mind and turned out it all looked good. When it was out i changed the pilot bearing, and throwout bearing. Put it all back together and still getting a noise that seems to be coming from tranny thats like a light little knock or rattle. Its a mendeola s4 mated to a bone stock ls2. The noise that im hearing is when the car is running in neutral. Like when you start it up in the garage. Anything im not thinking of that could be confusing me and making the noise and making me think its the trans? Any advice appreciated

 
Tapping valve on the engine…

Did you use a scope to pinpoint the location?

 
first if you push the clutch and put it in gear does the noise go away. if the noise doesn't go away  then the problem is not in the trans in gear with the clutch in nothing is moving in the trans. if the noise is still there check all the engine mount bolts and trans mounting look for ant cracked tubes. also does the noise change with rpm or wile driving

 
For anyone interested, i hate when people dont follow up on threads with the solution, as that is normally the only part that you jump to the end to read. Turns out, whoever setup the clutch initially, used some bigger arp bolts in the flywheel, which is great until they start to rub against your clutch plate because there isnt enough clearance. Havnt gotten it back together yet, but 95% sure that was the noise. Regardless, it needed to be addressed anyway, im going to throw some oem bolts in there with the proper clearance. There were obvious wear marks on the clutch plate where it was rubbing. Cheers!

 
Trevor said:
For anyone interested, i hate when people dont follow up on threads with the solution, as that is normally the only part that you jump to the end to read. Turns out, whoever setup the clutch initially, used some bigger arp bolts in the flywheel, which is great until they start to rub against your clutch plate because there isnt enough clearance. Havnt gotten it back together yet, but 95% sure that was the noise. Regardless, it needed to be addressed anyway, im going to throw some oem bolts in there with the proper clearance. There were obvious wear marks on the clutch plate where it was rubbing. Cheers!
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If that was the source of the noise then it should have only made noise with the clutch pushed in and trans in gear right? With the clutch engaged (peddle not pushed) then the flywheel and disc would be rotating together and not able to rub against one another 

 
I have come across a few S5 transmissions over the years that would rattle like hell in neutral, but everything was cherry inside. The only theory I could come up with is that 1st gear is large diameter and narrow, spinning on a narrower needle bearing than the rest of the gears, and with maybe .015" of endplay, the gear was rocking enough to make it rattle like that. I have no real proof that is the cause. I can't say we have every really narrowed down the exact cause, it's only on a few transmissions.

That was an S5, an S4 has wider gears and full width bearings on all 4, so it's hard to say that is the problem. 

Another possible cause could be reverse gears. The intermediate idler gear (the one attached to the shift lever that engages the other reverse gears when thrown) is running full time on the mainshaft/input shaft reverse gear. It's possible that this gear is rattling around a bit between the teeth as well. 

These are all very difficult issues to sort out, especially when everything inside the trans looks perfect in the set up housings on the bench.

The flywheel bolts could be a source as well, but as already stated, these would only interfere if the clutch pedal was pushed down and the trans in gear. Otherwise they would be spinning with the clutch assembly locked up with the pedal out.

Don't rule out an issue inside the bell housing. Some of the twin plate clutch assemblies get really tight in the early VW bell housings, and the pressure plate could be hitting somewhere inside the bell housing. 

 
Maybe the bolts were fine size wise, but backed out and you're hearing the flywheel knocking around?

 
Hope you found it but from your original post you said noise was while idling in neutral, right? Wouldn't the dics and flywheel bolts be locked up. Noise when stepping on clutch with car stopped in gear would make sense to me for what you describe you found. Maybe I'm missing something. 

 
Is it a Dual disc clutch? The floater plate makes noise on those. Perfectly normal

 
I had an LS with the wrong bolts in the flywheel sticking out far enough to make a worn clutch slip put in the new correct bolts and new double disc clutch problem solved also it made a rattle in neutral but not as bad as op said his was

 
I had the rivets come out of the clutch friction pucks on a double disk. 

 
Figured it was the clutch setup 

A lot of times it is not the bolts it is the rivets on the 9'' clutch, if you need smaller head bolts we have 12point that take a 8mm socket, not to beat you up but what i do hate when members ask for help but dont give all the information, Example you said a S4, what belhousing, if you said the full size, then i would say the flywheel is hitting the side of the belhousing, but if it is the VW style, then the 9'' clutch can hit the rivets or the bolts.

 
J Alper said:
Figured it was the clutch setup 

A lot of times it is not the bolts it is the rivets on the 9'' clutch, if you need smaller head bolts we have 12point that take a 8mm socket, not to beat you up but what i do hate when members ask for help but dont give all the information, Example you said a S4, what belhousing, if you said the full size, then i would say the flywheel is hitting the side of the belhousing, but if it is the VW style, then the 9'' clutch can hit the rivets or the bolts.
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It is the VW bell housing with the 9 inch single disk clutch. you could see where the flywheel bolts we’re hitting the rivets on the clutch plate. I had the tranny gone through again, just for good measure, and the builder said that the magnet had a little more metal on it then he was happy with for only being one trip. Hopefully between the smaller flywheel bolts, and the trans getting gone through again, we won’t have any issues we shall see.

 
Sean@Weddle said:
I have come across a few S5 transmissions over the years that would rattle like hell in neutral, but everything was cherry inside. The only theory I could come up with is that 1st gear is large diameter and narrow, spinning on a narrower needle bearing than the rest of the gears, and with maybe .015" of endplay, the gear was rocking enough to make it rattle like that. I have no real proof that is the cause. I can't say we have every really narrowed down the exact cause, it's only on a few transmissions.

That was an S5, an S4 has wider gears and full width bearings on all 4, so it's hard to say that is the problem. 

Another possible cause could be reverse gears. The intermediate idler gear (the one attached to the shift lever that engages the other reverse gears when thrown) is running full time on the mainshaft/input shaft reverse gear. It's possible that this gear is rattling around a bit between the teeth as well. 

These are all very difficult issues to sort out, especially when everything inside the trans looks perfect in the set up housings on the bench.

The flywheel bolts could be a source as well, but as already stated, these would only interfere if the clutch pedal was pushed down and the trans in gear. Otherwise they would be spinning with the clutch assembly locked up with the pedal out.

Don't rule out an issue inside the bell housing. Some of the twin plate clutch assemblies get really tight in the early VW bell housings, and the pressure plate could be hitting somewhere inside the bell housing. 
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Thank you for all that info, I had a friend with an S5 that rattled as you are saying, and everything was perfect in the trans. Builder  told him that they are built for strength not to be quiet. lol

 
Trevor said:
It is the VW bell housing with the 9 inch single disk clutch. you could see where the flywheel bolts we’re hitting the rivets on the clutch plate. I had the tranny gone through again, just for good measure, and the builder said that the magnet had a little more metal on it then he was happy with for only being one trip. Hopefully between the smaller flywheel bolts, and the trans getting gone through again, we won’t have any issues we shall see.
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Remember to shift aggressive, a lot of metal comes from the Dogs engaging, or if you miss a shift like i do some times, 

 
J Alper said:
Remember to shift aggressive, a lot of metal comes from the Dogs engaging, or if you miss a shift like i do some times, 
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10-4. I appreciate all the feedback. This noise has now snowballed into the whole car being torn down to fix all the little things while im at it… expensive sport we all chose lol 

 
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