Syncro / VC / noise and vibes

1

So to follow on with my original newbie email stating I had a bad vibration/whine coming on at 100 kph, I've now had the one CV boot that was broken replaced (CV joint was serviceable), and at the same time had the tail shaft removed.


Took it to the freeway last night, and it cruises smoothly to 110kph now in 2WD mode. At least now I know my gearbox and diffs run smoothly, and there is no issue with loose wheels or wheel balance. 


Also when inspecting at time of tail shaft removal, I found there was a lot of play (more than I'd expect) in the tail shaft, and also the VC looked a bit oily underneath and had a crude bead of sealant along its bottom edge. 


So now what? Can the tail shaft be balanced, and if so how? And/or, should I be looking into more testing / rebuilding / replacing the VC?  


I should add that now in 2WD mode the van feels a lot smoother and less noise and vibrations at all speeds than when running with the tail shaft fitted, which leads me to believe the VC may be the culprit and I may have been running in full (VC locked or cooked) 4WD mode hence the problems I was noticing.


Thoughts?


2
Suggestions:

1. Try tyre and wheel balance.

2. Something you did with that CV boot seems to have had an affect.
May be time to replace the CVs,
and when you do replace the bolts.

Years ago, one Sunday, in the Queensland back blocks, 
I was cruising my SYNCRO at 130.
Smooth as,  even with a set of Michelins on their last legs.

 




On 25 May 2018, at 12:25 PM, lepews@me.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com> wrote:



So to follow on with my original newbie email stating I had a bad vibration/whine coming on at 100 kph, I've now had the one CV boot that was broken replaced (CV joint was serviceable), and at the same time had the tail shaft removed.


Took it to the freeway last night, and it cruises smoothly to 110kph now in 2WD mode. At least now I know my gearbox and diffs run smoothly, and there is no issue with loose wheels or wheel balance. 


Also when inspecting at time of tail shaft removal, I found there was a lot of play (more than I'd expect) in the tail shaft, and also the VC looked a bit oily underneath and had a crude bead of sealant along its bottom edge. 


So now what? Can the tail shaft be balanced, and if so how? And/or, should I be looking into more testing / rebuilding / replacing the VC?  


I should add that now in 2WD mode the van feels a lot smoother and less noise and vibrations at all speeds than when running with the tail shaft fitted, which leads me to believe the VC may be the culprit and I may have been running in full (VC locked or cooked) 4WD mode hence the problems I was noticing.


Thoughts?





3
Suggestions:

1. Try tyre and wheel balance.

2. Something you did with that CV boot seems to have had an affect.
May be time to replace the CVs,
and when you do replace the bolts.

Sorry maybe I wasn't clear in my description? It now runs totally smooth all the way to speed limit with the tail shaft removed, so I'm pretty sure the wheels/tyres are well balanced. Also the the CV was checked when the boot was replaced, and found to be fine - all we did was fit a new boot to replace the perished one.

So it's now fine - no vibes, no noise - without the tail shaft driving the front wheels. So I thought the problem lies with the tail shaft and/or VC, am I not on the right track here?

Sorry Peter I'm confused!


4
All I gave was a classical list of where I’d be looking.

There was a time in my experience when tail shaft balance was an issue, but not for a SYNCRO. 
In those days we were talking about rear wheel drive cars,  the tail shaft of which was a long heavy tube, with a universal joint on each end.
We used to start with the universal joint bolts, then check the UJs, 
then if nothing else worked hand the whole shaft over to an engineering shop so that they could check it for balance.

I’m not into removing SYNCRO drive shafts and driving around.
So cannot help.





On 25 May 2018, at 2:38 PM, lepews@me.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com> wrote:



Suggestions:

1. Try tyre and wheel balance.

2. Something you did with that CV boot seems to have had an affect.
May be time to replace the CVs,
and when you do replace the bolts.

Sorry maybe I wasn't clear in my description? It now runs totally smooth all the way to speed limit with the tail shaft removed, so I'm pretty sure the wheels/tyres are well balanced. Also the the CV was checked when the boot was replaced, and found to be fine - all we did was fit a new boot to replace the perished one.

So it's now fine - no vibes, no noise - without the tail shaft driving the front wheels. So I thought the problem lies with the tail shaft and/or VC, am I not on the right track here?

Sorry Peter I'm confused!





5

Hi Gaetan,


I can't recall anyone ever reporting here of a VC that whines or causing a bad vibration. But it has been reported here on a number of occasions of the propshaft causing vibration, not necessarily at the same road speed as yours. So yes, no.1 suspect is the propshaft uni joints.


I have heard of the propshaft being put in back to front!


Also, under your or the previous owner/s, has the propshaft and/or front diff and/or mounts been messed about with or removed/replaced/reinstalled? If so, perhaps the propshaft and/or front diff have NOT been reinstalled precisely in the  positions as they were originally, so this may be one other possibility causing vibration. 


My syncro specialist was most impressed when I presented to him my syncro with mating propshaft flanges and front diff mating surfaces pre-marked precisely with white enamel paint lines. Made his job a whole lot simpler and reassuring during reinstallation, knowing everything went back in exactly as it was before, especially given I had no drivetrain vibrations before nor since.


Perhaps also research all there is available on principles of propshaft alignment and mushroom function.


Hint: If you ever feel the desire to replace original OEM propshaft or CV connecting bolts, despite them being in undamaged condition yet say 30 years old, my syncro drivetrain specialist would appreciate it if, instead of tossing them in the bin, post them to him instead please. He wants to reuse them. Ta.


Cheers.

Ken 



From: Syncro_T3_Australia@yahoogroups.com <Syncro_T3_Australia@yahoogroups.com> on behalf of lepews@me.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com>
Sent: Friday, 25 May 2018 12:25 PM
To: Syncro_T3_Australia@yahoogroups.com
Subject: [Syncro_T3_Australia] Syncro / VC / noise and vibes
 
 

So to follow on with my original newbie email stating I had a bad vibration/whine coming on at 100 kph, I've now had the one CV boot that was broken replaced (CV joint was serviceable), and at the same time had the tail shaft removed.


Took it to the freeway last night, and it cruises smoothly to 110kph now in 2WD mode. At least now I know my gearbox and diffs run smoothly, and there is no issue with loose wheels or wheel balance. 


Also when inspecting at time of tail shaft removal, I found there was a lot of play (more than I'd expect) in the tail shaft, and also the VC looked a bit oily underneath and had a crude bead of sealant along its bottom edge. 


So now what? Can the tail shaft be balanced, and if so how? And/or, should I be looking into more testing / rebuilding / replacing the VC?  


I should add that now in 2WD mode the van feels a lot smoother and less noise and vibrations at all speeds than when running with the tail shaft fitted, which leads me to believe the VC may be the culprit and I may have been running in full (VC locked or cooked) 4WD mode hence the problems I was noticing.


Thoughts?


6
Hi Ken and thanks for the useful info.

When checking the prop shaft in situ it seemed to have higher than normal amount of play, I will check the U joints to ensure they're serviceable.

It's difficult to get reliable service info as the previous owner is very old and uncontactable, and I think the van sat for quite a few years as he got older and the last service records are too faded to read.
I guess I'll just have to go through everything with the service manual and find out what's in or out of spec, but is there an obvious way to tell whether the shaft was mounted correctly or back to front?
Also if for some reason it was disturbed and re-mounted out of balance, is there a procedure to re-establish balance?

Quite technical questions I know, and I wouldn't mind a chat with your syncro specialist if you can forward his details as I don't have anyone who really knows these things well handy.

Thanks!
Gaetan
7
Hi Gaetan,

So it was the tail shaft ? There's a company just near me that will balance it.
Replacing the bushes in the drive shaft is a bit more problematic. If you don't mind a bit of noise just leave it.
Or ask if they can machine and insert new bushes.
Next priority if it were my van would be a decoupler. Takes a lot of strain off the gearbox / drivetrain.
Welcome to the world of Syncro $

Mark
8
Hi Mark,

well removing the tailshaft did remove all vibes/whine/noise, but I'm still unsure whether the tailshaft itself is the culprit.

Inspecting the VC I thought it looked suspicious - it's oily underneath and has a big bead of crudely applied sealant on its lower coupling to the gearbox, so I am wondering if in fact it's cooked, it may not even have any silicone left in it.. in which case it's possible it's locked permanently and driving the front wheels all the time, which surely isn't a great thing at 100+ kph and could be the reason for the whine and vibrations you felt when we reached 100.

Thanks for the link to finaldrive though, I may take the drive shaft to them to have it checked anyway :)

cheers
Gaetan


9
How did you inspect the VC? Did you take the front diff out? T3’s VC is inside the front diff. 
I’m assuming you are talking about the conical part at the front of the gearbox?...

Sent from my iPhone

On 26 May 2018, at 13:01, lepews@me.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com> wrote:

 

Hi Mark,


well removing the tailshaft did remove all vibes/whine/noise, but I'm still unsure whether the tailshaft itself is the culprit.

Inspecting the VC I thought it looked suspicious - it's oily underneath and has a big bead of crudely applied sealant on its lower coupling to the gearbox, so I am wondering if in fact it's cooked, it may not even have any silicone left in it.. in which case it's possible it's locked permanently and driving the front wheels all the time, which surely isn't a great thing at 100+ kph and could be the reason for the whine and vibrations you felt when we reached 100.

Thanks for the link to finaldrive though, I may take the drive shaft to them to have it checked anyway :)

cheers
Gaetan


10
Hi Beau,

yes I did mean the conical part at the front of the gearbox - that looked like the VC to me from pictures I've seen, but maybe I'm totally wrong? I didn't realise the VC is part of the front diff? 

Sounds like I need to do a helluva more research and RTFM before I start delving in!

11
Hey.

Yes, that part is just the output housing. You can put decoupler in there.
VC is inside the front differential. 
What you described is most likely out of balance main propshaft. Might be just U-joint, so it gets more out of balance at higher speeds...
Take it to a shop and let them spin it and check, what's happening.

Cheers
12
Great, thanks for that. I've already contacted a prop shaft specialist near me, waiting to hear back from them. I'll have it checked and balanced if needed, then refit and see what happens.

Fingers crossed that's all there is!
13

Hi Gaetan,


The VC is in the final drive (front diff) box over the front wheels, not at the front of the gearbox. What you've been looking at is where a decoupler would be installed if you so choose to. So you may have a gearbox fluid leak if its wet there.


Seriously I suggest you need to do lots more research before embarking on any action to solve the vibration issue.

For starters, the following link takes you to a US VW forum, the topic is exactly what you are experiencing, the lengths to which many have gone to solve it and perhaps at the end of the topic, a likely solution. What you asked me before about alignments, is also covered here. . . 

Goto: https://www.thesamba.com/vw/forum/viewtopic.php?t=627887&highlight=propshaft

Years ago, from memory, I believe a past member here with the vibration issue did solve his using the same solution ... replace all rubber mounts to gearbox and front diff. His name was Ben Croft. Someone else here may be able to confirm this outcome.


If you go down the propshaft testing and remediation route, the following is worth a read:

Goto: http://www.gowesty.com/tech-article-details.php?id=51


The mushroom (or donut) is normally located nearest to the gearbox.


There's been discussion here and elsewhere in the past (and again, I believe Ben Croft did it) about at least trying a novel procedure to see if the vibration has something to do with misalignment of the front diff.

From memory it was to do with loosening all the bolts that hold the front diff in place and going for a drive for a while and seeing if the front diff can realign itself and see if that is a solution or not. Whether or not anyone has had success with this trial procedure, I do not know. Perhaps someone else has something to add about it.

If you embark on this, then at least mark the present position first, then see after the trial whether it has shifted, then decide whether to leave it there or return it to its previous position.


Cheers.

Ken


  








From: Syncro_T3_Australia@yahoogroups.com <Syncro_T3_Australia@yahoogroups.com> on behalf of lepews@me.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com>
Sent: Saturday, 26 May 2018 2:38 AM
To: Syncro_T3_Australia@yahoogroups.com
Subject: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes
 
 

Hi Ken and thanks for the useful info.


When checking the prop shaft in situ it seemed to have higher than normal amount of play, I will check the U joints to ensure they're serviceable.

It's difficult to get reliable service info as the previous owner is very old and uncontactable, and I think the van sat for quite a few years as he got older and the last service records are too faded to read.
I guess I'll just have to go through everything with the service manual and find out what's in or out of spec, but is there an obvious way to tell whether the shaft was mounted correctly or back to front?
Also if for some reason it was disturbed and re-mounted out of balance, is there a procedure to re-establish balance?

Quite technical questions I know, and I wouldn't mind a chat with your syncro specialist if you can forward his details as I don't have anyone who really knows these things well handy.

Thanks!
Gaetan

14

Gaetan,

If the silicone fluid in your VC has hardened (aged/overheated/burnt etc), then the VC never fully deactivates, so its going/gone aggressive, even worse when hotter and higher internal pressure during a long trip.

If the seals of the VC have leaked silicone due mostly to abnormally high internal pressures, then the VC normally goes passive (inactive). In which case the leaked silicone would be mixing in with the front diff fluid ... not a good idea.

Ken



From: Syncro_T3_Australia@yahoogroups.com <Syncro_T3_Australia@yahoogroups.com> on behalf of Ken Garratt unclekenz@hotmail.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com>
Sent: Saturday, 26 May 2018 9:19 PM
To: Syncro_T3_Australia@yahoogroups.com
Subject: Re: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes
 
 

Hi Gaetan,


The VC is in the final drive (front diff) box over the front wheels, not at the front of the gearbox. What you've been looking at is where a decoupler would be installed if you so choose to. So you may have a gearbox fluid leak if its wet there.


Seriously I suggest you need to do lots more research before embarking on any action to solve the vibration issue.

For starters, the following link takes you to a US VW forum, the topic is exactly what you are experiencing, the lengths to which many have gone to solve it and perhaps at the end of the topic, a likely solution. What you asked me before about alignments, is also covered here. . . 

Goto: https://www.thesamba.com/vw/forum/viewtopic.php?t=627887&highlight=propshaft

Years ago, from memory, I believe a past member here with the vibration issue did solve his using the same solution ... replace all rubber mounts to gearbox and front diff. His name was Ben Croft. Someone else here may be able to confirm this outcome.


If you go down the propshaft testing and remediation route, the following is worth a read:

Goto: http://www.gowesty.com/tech-article-details.php?id=51


The mushroom (or donut) is normally located nearest to the gearbox.


There's been discussion here and elsewhere in the past (and again, I believe Ben Croft did it) about at least trying a novel procedure to see if the vibration has something to do with misalignment of the front diff.

From memory it was to do with loosening all the bolts that hold the front diff in place and going for a drive for a while and seeing if the front diff can realign itself and see if that is a solution or not. Whether or not anyone has had success with this trial procedure, I do not know. Perhaps someone else has something to add about it.

If you embark on this, then at least mark the present position first, then see after the trial whether it has shifted, then decide whether to leave it there or return it to its previous position.


Cheers.

Ken


  








From: Syncro_T3_Australia@yahoogroups.com <Syncro_T3_Australia@yahoogroups.com> on behalf of lepews@me.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com>
Sent: Saturday, 26 May 2018 2:38 AM
To: Syncro_T3_Australia@yahoogroups.com
Subject: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes
 
 

Hi Ken and thanks for the useful info.


When checking the prop shaft in situ it seemed to have higher than normal amount of play, I will check the U joints to ensure they're serviceable.

It's difficult to get reliable service info as the previous owner is very old and uncontactable, and I think the van sat for quite a few years as he got older and the last service records are too faded to read.
I guess I'll just have to go through everything with the service manual and find out what's in or out of spec, but is there an obvious way to tell whether the shaft was mounted correctly or back to front?
Also if for some reason it was disturbed and re-mounted out of balance, is there a procedure to re-establish balance?

Quite technical questions I know, and I wouldn't mind a chat with your syncro specialist if you can forward his details as I don't have anyone who really knows these things well handy.

Thanks!
Gaetan

15
Hi Gaetan,

if the VC was rooted ( technical term ) you would have noticed severe binding of the front wheels turning on bitumen. So probably not the culprit.
Also everything is still turning without the prop shaft connected, so no vibes means likely no issues with anything else.
I think getting the prop shaft balanced and uni's checked will solve the problem.
My shout if I'm wrong !

Mark
16
I'm awaiting to hear from FDE - hopefully they will be able to help and that will solve my problem!

When you say having the uni's checked, do you mean the U-joints either end of the tail shaft? 

And thanks to all who posted in this topic - all great advice and much appreciated!
17
Hi Gaetan,
Sure, if you so choose. Might get lucky.

There's been previous discussion here about replacing joints with a particular model designed more for agricultural use. Maybe not quite up to scratch but lacking an alternative. Not been there so can't help further, someone else may have more specific info.
Cheers.
Ken

From: lepews@me.com [Syncro_T3_Australia]
Sent: Monday, 28 May 1:35 PM
Subject: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes
To: syncro_t3_australia@yahoogroups.com


 
I'm awaiting to hear from FDE - hopefully they will be able to help and that will solve my problem!

When you say having the uni's checked, do you mean the U-joints either end of the tail shaft? 

And thanks to all who posted in this topic - all great advice and much appreciated!



18
Also,
I read somewhere that local refurbishers/balancers of the likes of tailshafts/propshafts do not have test equipment that maximum rotate any where near as far as our propshafts do. Limited to say 1000rpm. If valid, then your vibration coming in in excess of 100kph may not show up. I stand corrected if incorrect.
Cheers.
Ken




Sent from Samsung tablet



-------- Original message --------
From: "Ken Garratt unclekenz@hotmail.com [Syncro_T3_Australia]" <Syncro_T3_Australia@yahoogroups.com>
Date: 28/05/2018 3:17 PM (GMT+10:00)
To: syncro_t3_australia@yahoogroups.com
Subject: Re: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes


 

Hi Gaetan,
Sure, if you so choose. Might get lucky.

There's been previous discussion here about replacing joints with a particular model designed more for agricultural use. Maybe not quite up to scratch but lacking an alternative. Not been there so can't help further, someone else may have more specific info.
Cheers.
Ken

From: lepews@me.com [Syncro_T3_Australia]
Sent: Monday, 28 May 1:35 PM
Subject: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes
To: syncro_t3_australia@yahoogroups.com


 
I'm awaiting to hear from FDE - hopefully they will be able to help and that will solve my problem!

When you say having the uni's checked, do you mean the U-joints either end of the tail shaft? 

And thanks to all who posted in this topic - all great advice and much appreciated!



19

On Mon, 28 May 2018, 3:47 pm Ken Garratt unclekenz@hotmail.com [Syncro_T3_Australia], <Syncro_T3_Australia@yahoogroups.com> wrote:

Also,
I read somewhere that local refurbishers/balancers of the likes of tailshafts/propshafts do not have test equipment that maximum rotate any where near as far as our propshafts do. Limited to say 1000rpm. If valid, then your vibration coming in in excess of 100kph may not show up. I stand corrected if incorrect.
Cheers.
Ken




Sent from Samsung tablet



-------- Original message --------
From: "Ken Garratt unclekenz@hotmail.com [Syncro_T3_Australia]" <Syncro_T3_Australia@yahoogroups.com>
Date: 28/05/2018 3:17 PM (GMT+10:00)
To: syncro_t3_australia@yahoogroups.com
Subject: Re: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes


Hi Gaetan,
Sure, if you so choose. Might get lucky.

There's been previous discussion here about replacing joints with a particular model designed more for agricultural use. Maybe not quite up to scratch but lacking an alternative. Not been there so can't help further, someone else may have more specific info.
Cheers.
Ken

From: lepews@me.com [Syncro_T3_Australia]
Sent: Monday, 28 May 1:35 PM
Subject: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes

I'm awaiting to hear from FDE - hopefully they will be able to help and that will solve my problem!

When you say having the uni's checked, do you mean the U-joints either end of the tail shaft?

And thanks to all who posted in this topic - all great advice and much appreciated!



20
It doesn’t work that way. Many modern wheel balancers spin very slowly. It’s all about the quality of the sensors. If there is play in the unis have them replaced by the professionals and then they will balance it. You can also replace the bush and o ring under the donut. Greg

Sent from Greg's iPhone

On 28 May 2018, at 4:28 pm, Peter Bellamy wanderingstar911@gmail.com [Syncro_T3_Australia] <Syncro_T3_Australia@yahoogroups.com> wrote:

 


On Mon, 28 May 2018, 3:47 pm Ken Garratt unclekenz@hotmail.com [Syncro_T3_Australia], <Syncro_T3_Australia@yahoogroups.com> wrote:
 

Also,
I read somewhere that local refurbishers/balancers of the likes of tailshafts/propshafts do not have test equipment that maximum rotate any where near as far as our propshafts do. Limited to say 1000rpm. If valid, then your vibration coming in in excess of 100kph may not show up. I stand corrected if incorrect.
Cheers.
Ken




Sent from Samsung tablet



-------- Original message --------
From: "Ken Garratt unclekenz@hotmail.com [Syncro_T3_Australia]" <Syncro_T3_Australia@yahoogroups.com>
Date: 28/05/2018 3:17 PM (GMT+10:00)
To: syncro_t3_australia@yahoogroups.com
Subject: Re: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes


 

Hi Gaetan,
Sure, if you so choose. Might get lucky.

There's been previous discussion here about replacing joints with a particular model designed more for agricultural use. Maybe not quite up to scratch but lacking an alternative. Not been there so can't help further, someone else may have more specific info.
Cheers.
Ken

From: lepews@me.com [Syncro_T3_Australia]
Sent: Monday, 28 May 1:35 PM
Subject: [Syncro_T3_Australia] Re: Syncro / VC / noise and vibes
 
I'm awaiting to hear from FDE - hopefully they will be able to help and that will solve my problem!

When you say having the uni's checked, do you mean the U-joints either end of the tail shaft? 

And thanks to all who posted in this topic - all great advice and much appreciated!