Syncro transmission mounts- torqe - balancing

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burnzdog
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Syncro transmission mounts- torqe - balancing

Post by burnzdog »

Hi all,

Since having the front Diff out recently I have noticed after reinstalling it there seems to be more Drive train noise and and more vibration on cornering. THis coudl all be in my head of course but being that its been out and back in there is a chance something has changed.

A few questions. I cannot seem to find any definitive answer to the correct torque settings for the mount bolts? also I realised my error by not marking the drive train and front diff before removing.
Is there a way to calibrate drive train and front diff? I read that by loosenign off the front mounts to allow the diff to sit correctly before tightening mounts can help?

Any ideas appreaciated.

Matt

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Re: Syncro transmission mounts- torqe - balancing

Post by silverbullet »

Most common cause is wear in the propshaft. The u/j's work at such a small angle that wear is highly focussed and it is impossible to put everything back in exactly the same position.
Get the prop refurbed and a lot of the noise will disappear.

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Aidan
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Re: Syncro transmission mounts- torqe - balancing

Post by Aidan »

did you fit the prop to the front diff before tightening the mount bolts ? mounts should be the last thing to be tightened up
Did both the spacer rings between the driveshafts and output flanges get refitted ?
loosening the bolts holding the rubber mounts and the two holding the front mount plate and doing a short drive can help to centralise it all and put it in a neutral position and then retighten the bolts
there's no figures in Bentley for the torque as you'll be using a spanner on one end of the rubber mount bolts,nominally probably 30Nm for the M10s and 45 Nm for the M12s is plenty, good spanner tight with 17mm spanners, the front mount plate can only be done with spanners so that's a limiting factor but those have no washers so once the nut and head of bolt lock up it's tight, and you have to undo them with spanners so don't go overboard. Locking nuts on the rubber mount bolts so they won't be coming loose anyway

Why was the diff out, VC refurb or driveshaft refurbs ?

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burnzdog
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Re: Syncro transmission mounts- torqe - balancing

Post by burnzdog »

Aidan wrote:did you fit the prop to the front diff before tightening the mount bolts ? mounts should be the last thing to be tightened up Yep
Did both the spacer rings between the driveshafts and output flanges get refitted ? Yep
loosening the bolts holding the rubber mounts and the two holding the front mount plate and doing a short drive can help to centralise it all and put it in a neutral position and then retighten the bolts
there's no figures in Bentley for the torque as you'll be using a spanner on one end of the rubber mount bolts,nominally probably 30Nm for the M10s and 45 Nm for the M12s is plenty, good spanner tight with 17mm spanners, the front mount plate can only be done with spanners so that's a limiting factor but those have no washers so once the nut and head of bolt lock up it's tight, and you have to undo them with spanners so don't go overboard. Locking nuts on the rubber mount bolts so they won't be coming loose anywayOK, will give it a go

Why was the diff out, VC refurb or driveshaft refurbs ? Came down to you to be checked out :)

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Re: Syncro transmission mounts- torqe - balancing

Post by dokamonkeys »

Hi Matt. How are you getting on with this?
I dive in and out of the forum and to my shame am not a contributor but as you know this is of some interest personally
When your diff came across to Wales we couldn't find any issues worth, at the time, any more input than our usual strip, assess, and measure. There was no play in the pinion bearing and it measured in spec. As a matter of course the backlash was reset, again to spec, and everything was buttoned up good to go.
The VC was, in our opinion, a bit tight. Now we can't give any more than an experienced best advice errr advice on this but nevertheless you'll recall it was mentioned at the time.
I seem to recall the reason we had the diff was because of an errant ABS ring doing peek a boo and causing an odd rattling that at the time was thought to be more internal than it actually was.
Soooooo, if actioning the 'vancafe' loose mounts and driving in a straight line for a few yards, stopping and bolting it all tight (what I've always done hehe) doesn't work then I'd be looking at ujs on the prop and getting the VC done by Ian.
Out of interest, are the diff mounts in good condition and original VW?
Neil
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burnzdog
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Re: Syncro transmission mounts- torqe - balancing

Post by burnzdog »

Hey Neil good to hear from you.

Yeah thanks for your input, yeah spot on with this, van is fine just as i mentioned it just feels like there is more vibration than before is all. I just wondered being that I didnt mark the prop before removing DIff whether this would have an impact. THe diff itself is fine, and all other issues have now gone, I also took on board that the VC will need doing so will plan to do this later in the year along with the ujs.

Diff mounts are original and having had them out for good inspection they look fine, I wasnt getting the vibration at a certain speed just more of a vibration when turning. However, I may just replace as I knwo these things can look OK but still be problematic.

After trying the loosen method it did seems to help, but in the grand scheme of things i no idea where its normal or noisy compared to other vans.  I will still get other things done as planned later this year. 

Hope your well anyway chap, and thanks for help as always!

 

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