If the master or slave cylinder had failed, I'd expect the clutch pedal would be limp or have loads of free travel ...

I'd suspect either the friction material has broken up or an oil leak has contaminated it, as Oli Rag said above. Best of luck with it.

I've had sudden clutch slip from a gearbox oil seal letting go on an old Austin Maxi.

The symptoms were obvious, a patch of oil under the bellhousing and temporary resumption of grip if I slipped it enough to burn off the surface oil.

Thanks e.doc.
Question: - Can a dual-mass flywheel completely fail (absence of transmitting drive), suddenly, with no previous jerkiness or noises or difficulties of gear change, no previous symptoms or indications at all ? I have 'googled' some, but not yet found similar symptoms.
Also - as stated, there was in fact some transmission friction for a while, enough to first move the car on the level at a very low speed (engine in first gear, on idle speed) though zero possibility of accelerating, and soon losing all friction.

The motor still runs normally, and no abnormal sound or feel when using the clutch pedal - no vibrations, noises of 'interference' of pieces rubbing/grinding past each other... nothing at all to say there is anything wrong (!)... except there is no drive between engine and road wheels!!

Also - no warning lights came on the dash: would I expect something from the ECU ?

Thanks again for all replies!

Thanks Peter. (And presumably you lost all power - because of the diff...)

Curious thing is that I had some traction for a time after... not much, but enough to move on the level... for a short while.

Anybody please -- comments/info on this aspect - of potential drive train problem - ie especially differential/ gearbox... /drive shaft/ joints/ ? - (ie. other than clutch?)

... keeping in mind the lack of signs of anything 'going' before it had 'gone' !

Thanks to all

Would you imagine some bad sounds when those shaft splines first began to rotate? I have had no adverse symptoms... nothing at all!

Any (roadside) test that I can do to differentiate between a clutch problem, and another cause of 'disconnected drive between engine and road wheels' - a "rotating diff" (somehow...) or some internal malfunction of the gearbox, or anything??

By jacking up one front wheel and turning it while in gear, it should normally turn the engine. But if the diff is 'gone', or the clutch is 'gone' - it will turn in both cases, won't it?
All I might feel is potentially some change in stiffness to rotation, if there is still some friction remaining (but insufficient to drive the car...)

And in neutral, it should turn anyway... Or am I confusing myself...?

So I don't see a test manoeuvre, but has anyone any ideas?

I'm afraid otherwise of one of these stories where x, y and z (or French equivalent...) are changed 'in case'/ or 'maybe it's the...'... and it's all put back - with the same trouble as before... or a whopping bill for unnecessary labour and parts! :-(

Edited by grayman on 23/09/2013 at 18:51

@ Peter - thanks for that.

I would probably have tried a 'reversing direction' on turning a wheel - but may not have thought to do it rapidly. Appreciated!

Unfortunately I'm not going to be able to get both wheels up at the same time (equipment and opportunity...) - and I confess I didn't think of it -- so I appreciate that one too!

Other test mentioned to me:
Try with motor running, without using clutch, to go through the gears... results?

Anyone with any others?

Thanks, guys.

UPDATE:
Sorry this is such a big post... I don't see how to make it shorter and still include the info... I have now run some tests on the vehicle...

PLEASE, please comment/help if you have knowledge and get insight from the following:

Car standing for 2 days: no abnormal oil leaks, normal level of hydraulic fluid, normal clutch pedal feel and movement (possibly a bit lighter than normal… but not markedly so).No visible signs of anything wrong. Starts easily, no abnormal sounds in neutral.

TESTS:
1) Engine off - without using clutch. Select all gears.
All gears selectable, feels normal selection. Same if clutch depressed.

2) Engine on – without using clutch. Select all gears
All gears selectable (engine running) - incl. reverse; some patience and steady pressure needed esp for 1 st ; other gears progressively less so. Car would start to try to move – (especially in 1 st, moved maybe 9” )– then almost ‘go through a resistance point’ then stop trying to move – (this is without brakes) – in 1 st it was almost as if it wanted to ‘go up over a curb’, or other resistance point, then ease off… rather than just rolling forwards – (curious!) moved maybe 9”

3) Engine off - Raise ONE front wheel and rotate manually both directions; test both sides.
Offside – rotatable ‘forwards’ in all forward gears, but not in reverse gear (engine resistance?)
Forwards: First there is resistance for some turning (maybe ½ - ¾ revolution in 1 st , less in others), then it eases off and can turn fairly freely.
Backwards: strong resistance in all forwards gears, not in reverse (was rotatable).

Nearside – Feels different to offside – could rotate both directions. But again, especially gears 2-5, resistance would slacken off after getting through a resistive phase. 1 st and reverse feel similar – a lot more resistance, and I am not sure if I am trying to turn the engine (definitely not, in higher gears).

4) Engine off - BOTH wheels raised; rotate both directions: (presumably testing differential and universal joints, shafts only, connecting both wheels – not its connection to gearbox) – one wheel rotates the other in opposite direction – all gears incl. reverse.

Changing direction rapidly gives a ‘normal-sounding’ “clonk….clonk” as slack is taken up and the other wheel is braked and reversed direction. Feels normal to me.

5) Engine on: ONE wheel raised, test all gears, test both sides.
A definite difference offside/nearside….
Offside – test 1: all gears could be stopped by hand on wheel, or higher gears did not rotate wheel. Reverse - unfortunately I did not note reaction – and don’t remember (it was getting late, I was hurrying…)
Nearside – test 2: Different! Nearside, in 1 st (maybe second), wheel could not be stopped manually, or by friction from wheel spanner to tyre. If using brakes – it could be stopped but set up a nasty chattering sound’ – the kind of sound when there are two metal plates that rotate together – but they are loose – you get a kind of ‘chattering’ and ‘whirring’ sound… (if you understand!!). Higher gears could be stopped by hand (2 nd needed care…) – always with this ‘chattering’ sound.

Offside repeated – test 3: NOTE: after testing nearside: initially now it is a similar result, with the ‘chattering’ (not heard the first time…) – then it settled as test continued, to ‘not chattering’ – ie. basically as it was before - though it is a little noisier… something not entirely ‘as before’

Current conclusions : But – PLEASE ADVISE if you have knowledge of this!!

a)-- the “clutch problem” -- I am now questioning this, having a different result nearside/offside… I cannot see a logic for it being clutch … but I have no experience of dual-mass flywheels... is that a game-changer? I state again there was no previous symptoms, no ‘chatter’ or vibration or difficulty selecting gears, no indication of clutch slip, before the sudden onset, as seems to be for people I have googled on this question.

b)-- The differential -- SEEMED to connect normally the both sides (road wheels)…. though its connection to gearbox has not been isolated. And – its ‘test’ was with both wheels free to rotate – just sensing the resistance to inertia of changing direction. When one wheel was on ground, and in gear, the feel was completely different… I could rotate a road wheel while in gear

c)-- universal joints, shafts etc connecting the two wheels – seem in normal order

d)-- the gearbox would SEEM to me to be the culprit… but just what has happened, is beyond my depth.

PLEASE – if you have constructive knowledge – or need more info – PLEASE comment!

I am hoping for a strong diagnosis if at all possible!

And yes – I am aware that the only real answer is to take it apart… - though once it is with a garage, I am stuck with whatever they dish me up, good or bad!

Will I need a new gearbox? and total cost?
Is something repairable – and worth repairing? (guess cost??)
What of the clutch/dual-mass flywheel? cost clutch / clutch and DMF?
.
Any other comments!!!

Many, many thanks!!

Grayman

" normal clutch pedal feel and movement (possibly a bit lighter than normal… but not markedly so)"

A possible clue is the lighter clutch pedal ... the only reason a clutch pedal can be lighter must be connected with the pressure plate assembly ...

The diaphragm spring plate is like a dished plate with fingers and pivots on pins and sits convex, when pressed it moves to a concave shape, this lifts the face plate and releases the clutch friction plate ...

I have only seen this once in my long career in the motor trade (am now retired) ...

I had one that the diaphragm plate split , this weakened the clutch sufficiently to give a weaker pedal but very little pressure to clamp the friction plate ...

This is a possibility ...

Its very unlikely that the gearbox would have failed, the input and output shafts are very substantial so unless all the gears had lost their teeth you will still have drive through the box. Unlikely as it seems I would say its the clutch that has had some sudden mechanical failure. I have never heard of a DMF completely falling apart and causing lack of drive, they normally give warning noises if they are worn.

I hacve a 406 and C5 both with Hdi engines and both at around 200,000 miles, still with original clutches and flywheels, the clutches on both vehicles are worn as they disengage right at the top of the pedal but they were like that when I bought them and have not got noticably worse in many thousands of miles so my personal opinion is sudden and complete clutch failure.

Haynes Manual? £14.51 from Amazon or about £10 from Abebooks.co.uk

Well - I had one very frustrated mechanic - but 'job is done'...or nearly -- and probably a long way round...

(I would still be v. interested to know the right way to get out the box??/simplest solution? He took out both drive shafts, through undoing both bottom ball jpoints - also the radiator and exhaust downpipe (filter) for easier access - other parts too - but a really great guy.)

So - result of trouble? A piece of plastic! PLASTIC -- in the 'heart' of the bi-mass flywheel... a 'spider' controlling positioning of the heads of a number of springs enclosed in tubs in a 'star' configuration -- it was broken in pieces... so the spring carriers moved, and... no more drive! The metal carriers at the central attachments of the 'star' configuration are all bent out of shape (effectively 'compressed' > made shorter, allowing the centre to rotate irrespective of the peripheral surface for the friction plate (or the toothed flywheel if you prefer: same effect).

So the dual mass no longer had 'drive' capacity... leaving me with a 'normal feeling' clutch pedal, and even engine/gearbox sounds -- but no 'go'.

I hope to post some pics. of this if you are interested.... meanwhile I pick up the tab of 1100€ or about £850 (not yet received bill...) - for a piece of PLASTIC given to me by manufacturers of a high-stress item: a clutch and flywheel! Incredible...

Enjoy your motoring...

grayman

Edited by grayman on 09/10/2013 at 16:21

I hate to say this but my mum had the same problems it seems to be a problem with them. She had to have whole new clutch fitted and when spoke to people seems alot go at 60k and just above yet citreon will not admit its faulty.