Judder changing down to second?

[Lance]

My 944s has always juddered when changing down from third to second especially at higher speed if I wait until it almost stalls in third then change down its fine, the gear leaver shakes and the clutch feels like its going to be shaken to death, any ideas, all other gears seem fine up and down, no fluid leaks clutch pedal feels fine just don't understand :-(

 

[DC911SC]

whats the mileage and age on the clutch?

a few possibilities

flywheel could be corroded or rusty a bit unlikely

gearbox could be bad - most likely! quote below from clarks garage:

"Bad sychros in the transaxle will cause difficult shifting. 944s are notorious for 2nd gear and sometimes 3rd gear sychros to go bad. If the transmission is difficult to shift when cold, particularly in second gear, and the shifting improves as the transaxle warms up, it's due to a bad synchro. The only permanent solution is to rebuild the transaxle. However, switching to a synthetic gear oil in the transaxle will most likely improve the shifting."

clutch could be toast.

I wouldn't recommend driving to stalling point and changing will damage so much from engine mounts etc etc

 

[George Elliott]

Lance, I would ask if the car is in regular ( 200 miles per week minimum) use?

Loads of people will tell you it needs a clutch. I have never replaced a clutch in 20 years of 944 turbo's.

I think from your explanation you know this unique "2nd gear down change behaviour" is not the symptoms of a failing clutch.

My hunch is the bare steel shaft the clutch spline slides on is corroded. The unique bit causing the behaviour is the ratio of 2nd gear. It could be the flywheel is not totally clean and a good rub with the clutch would help clean it up. bit brutal so a last resort.

I would operate the clutch mechanism for 10 minutes constantly with the car in neutral engine off, then take it for a run and see if the symptom disappears.

The constant operation may smooth out the corrosion between the spline male/female which is a clearance fit for a nice smooth movement, but which has become a shuddery movement caused by corrosion. Its an easy test. My car did this, although it was aggravated by a tiny leak from the heater valve above the bell-housing...

The rear gearbox mount and Master & Slave cylinders would be my next checks

Good luck
George
944t

 

[DarrylH]

Mine does this but I know it's the original clutch on its way out. It also judders backwards and forwards when in gear when letting off and accelerating at lower revs etc.

 

[Lance]

Thanks for all your advice first the engine was rebuilt 10k miles ago at 146k the bill for this included the clutch "reface" not sure what that is, clean up? the car does not judder on or off acceleration or lurch, the other thing is I posted on here a month ago a knocking noise coming from the rear which gets faster with speed sounds like cv joint "clicking noise" BUT it doesn't do it all the time, can go couple days and no noise then the next day noise all time then on and off, its quite loud, does in on and off throttle, just wondered if this was related to judder, gearbox? Or two separate problems, I use my car daily 36 ish miles

 

[George Elliott]

Lance, ...the reface, I hope its dimensionally true, and the surface finish is good. The clicking noise.....I did not respond last time because, in a way there are not many things it can be, on the other hand there are millions. Stones in disc's, wheel bearings, handbrake hub springs, suspension bushes, ARB bushes, Gearbox, Diff and CV's as you say.
George
944t

 

[LarJammer]

Lance, your problem is most likely the gearbox mount allowing the box to move around.

 

[Lance]

That is actually the most likely and explains the cv joint noise as well, just before I bought the car couple months ago it had a new gearbox mount! If this was not fitted properly or loose would this mean when the gearbox moves the cv joints are also moving causing them to "click" as they are out of alignment and the judder

 

[944 man]

Does the gearshift change as you corner? This can disclose a worn transaxle mount, too.

 

[Lance]

Do you mean change or jump out of gear, the gear leaver moves though

 

[944 man]

Does the ease/quality change? Does it become difficult as you are cornering?

 

[Lance]

Not noticed but will try and report back thanks

 

[944Fripp]

Mine has always done this. Took it to my local indie for their opinion and was told they could find no fault. It had a new clutch about 30k ago. Interesting about tying the clutch whilst engine off and in neutral, I'll try this too. Always assumed it was a quirk of the car!

It's different to setting off in first though, the judder is very common on S2's as it's the fuel shut off valve. Read it in a book somewhere so it must be true! []

 

[bmnelsc]

Clutch reface used to mean (in the old days) that the clutch linings were replaced on the original disc. This is not likely these days so more likely means they machined the flywheel to "reface" the clutch contact surface. Your juddering could be rust on the spline shaft (as per George) or could be the release bearing binding on the guide tube.

 

[TTM]

Many if not most 944S/S2 drivers suffer from this issue at one point, and some suggest the issue lies within the design of the clutch disc. There may be a problem with the rating of the springs.