[Terence Ledger]

Hi All, trying to diagnose a problem with my manual 968. On downshift into second gear sometimes the drive train will shudder and the car shudders. It is eliminated when you give her some revs and balance the clutch. If you do not it will shudder all the way to a stop or you depress the clutch.



It does not happen all the time but seems to be more regular.



Could it be a slipping clutch or could it be the gearbox? (or could it be a daft driver going to fast and not knowing how to heel and toe it so you keep the revs up).

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[flash]

clutch - what flywheel do you have?

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[PorscheDude]

I would guess that the Dual mass flywheel is on its way out.

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[banditsc]

Hom many miles are on the car and the clutch components?

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[Terence Ledger]

[quote name='banditsc' post='60601' date='Sep 26 2008, 03:43 PM']Hom many miles are on the car and the clutch components?[/quote]





The car has only has 52000 miles on her from new. I imagine all parts clutch flywheel etc are all standard original and never been replaced.

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[flash]

then yes, i concur - likely a DMF going out - it's that or a glazed disk - either way, the clutch would need to come apart to fix it



to be sure though, running down the road, if you lift off the throttle abrubtly, and step on it abrubtly, is there any backlash or clunking?

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[Terence Ledger]

[quote name='flash' post='60646' date='Sep 27 2008, 04:47 PM']then yes, i concur - likely a DMF going out - it's that or a glazed disk - either way, the clutch would need to come apart to fix it



to be sure though, running down the road, if you lift off the throttle abrubtly, and step on it abrubtly, is there any backlash or clunking?[/quote]



I will try that out tomorrow when I am out and report back.

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[p65356sc]

Good guess...........pressure plate. Ive had the same problem with my 356. a look at the pressure plate and it was obvious.

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[flash]

the pressure plates on these are pretty tough - the spring plates almost never fail - it's the nature of a "pull type" as opposed to a "push type" - grooves in the surface are another story, but no way to tell without taking it apart

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[Terence Ledger]

Ok I did the fast off the acelerator and quick back on. No Clunk, just the rear end stepped out as it was slightly wet.... It is easy to drive round the shudder. It is just annoying. It is going to a specialist on Friday for an adjustment to the shocks so will ask hin

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[flash]

ok - that takes drive line and such out of the equation - looks like it's in the clutch area - either failed DMF or glazed or chewed disk would be the most likely culprit here

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[Terence Ledger]

The glazed disk could be the problem as it does a lot of time on the nurburgring. Anyway will report back what happens next friday. I am glad the symptoms do not point to a gearbox.

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[flash]

i doubt it - i have glazed disks before, and it sounds a lot more like that than anything else - however, this is the hardest gear for the car, and you can quickly frag a disk from here - time to change it

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[link517]

I have this same exact problem. Just noticed recently, it only happens when i go down into 2nd gear. Is a definitive cause figured out? My car has 131k, and i have spotty records, if any of any previous maintenance. No word when the DMF was last replaced. RSBARN installed a reliable barely used dual mass flywheel and pressure plate at about 129k at the end of august this year.

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[flash]

hmmm - a few things can cause that

rear main is leak
deposits on the disk, pressure plate or flywheel
cooked disk
failing DMF

1. did this happen all of a sudden?
2. were there any odd circumstances (like having to slip the clutch up a hill, etc)
3. does it do it if you rev match?
4. does it do it both hot and cold?
5. have there been any odd smells?
6. is it smooth at take off?

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[link517]

1. only when exiting highway, downshifting to second, car is going 40-45mph
2. dont think so
3. does not do it if i rev match
4. dont know, first happened about a month ago, again when i took the car out last week, (both days in 40's)
5. no
6. yes

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[flash]

sounds like crap on the disk - it only does it in 2nd because of the torque in that gear

i'll chat with pete about what was done and see if i can further diagnose this

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[link517]

Sounds good, thanks.

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[flash]

i talked to pete

there was a ton of work done - it got all new stuff in any of the odd places that would cause this (new fork bearing, front input shaft, rear main seal, etc)

the only thing left really is crap on the disk - it's likely either you picked something up there that contaminated the disk, or you glazed the disk - not that this is the case, but i've seen this happen when people spend a lot of time in traffic and constantly slip the clutch, and especially with people who rest their foot on the clutch pedal

either way, the solution is probably going to be a new clutch disk

welcome to my world - i'm on my 6th disk in 2 years (different reason, but same pain)

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[Ryan]

Just rev-match like you should and live with it.

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