1,2 TDI clutch/ gearbox problems

After the extensive maintenance on my 1.2TDi (hydraulic unit and gear actuator rebuilt, new clutch, new gearbox oil, new brakes) I've had a clunking sound sometimes when the system uses the clutch. The "clunk" sounds when I accelerate from standstill after the car has been sitting for some time. I can also hear it about 60% of times when I slow down to traffic lights (it will sound at some downshift) and rarely I'll hear it when I release the accelerator and the car starts coasting (that's how I know it comes from the clutch operation). It will only sound once per "event".

Anyone have any idea what it could be? I'm thinking of maybe gearbox/engine mounts?
 
DKPowers said:
After the extensive maintenance on my 1.2TDi (hydraulic unit and gear actuator rebuilt, new clutch, new gearbox oil, new brakes) I've had a clunking sound sometimes when the system uses the clutch. The "clunk" sounds when I accelerate from standstill after the car has been sitting for some time. I can also hear it about 60% of times when I slow down to traffic lights (it will sound at some downshift) and rarely I'll hear it when I release the accelerator and the car starts coasting (that's how I know it comes from the clutch operation). It will only sound once per "event".

Anyone have any idea what it could be? I'm thinking of maybe gearbox/engine mounts?
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I get that occasionally on my 1.4TDI.

I have put it down to play in the driveshafts (haven't had chance to figure out which one (inner or outer, left or right) But I suspect the outer nearside CV joint (passenger side in a RHD car). I am also getting noise when cornering hard on a roundabout (not that I do that very often)

It might be worth checking out the driveshafts.

Steve B
 
New problem popped up today. After an about 100km journey, the car started to be "lurchy" or "jumpy" when creeping and at very low acceleration. Kinda like a child would use the clutch and accelerator ie. I set the car to drive and release the brake pedal but it doesn't move for a few seconds, then it seems to "release" itself in a lurchy or jumpy manner. Once I'm moving a bit faster, it feels fine.

What could be wrong? The car starts normally and has had new glow plugs put in just a while ago. The gear actuator and hydraulic pump where refurbished and the accumulator is new. There is plenty of hydraulic oil and I can change 4-5 gearchanges before the pump starts. Also the clutch was replaced. The car has done 235000 km. The right side drive shaft is worn but that shouldn't affect it, should it? I'm thinking maybe the clutch slave cylinder is on its way out?
 
I would agree with the last sentence. When the clutch actuator is on the way out, it becomes rather sluggish, just like us humans! If you move the lever to STOP quickly, you'll probably find it won't engage first gear. But if you take your time it will (or might)! Another symptom is failure to start with the lever in STOP. Someone on the German site is looking at using a Hall effect sensor as an alternative to the potentiometer.

RAB
 
Any way to make sure it's the slave cylinder? I'd hate to spend over 300€ on a part to find out it wasn't it. I've already poured so much money into this car...
 
Not really. VCDS won't diagnose it, as it won't a faulty accumulator. Has a basic setting been done recently? Was the creep adaptation completed? If you can do a basic setting and still start in STOP, I would say it was OK.

RAB
 
It starts in STOP normally and the basic setting was done when the hydraulics where overhauled around 7500km ago. Is the creep adaptation part of the basic setting procedure?
 
Yes, the creep adaptation is the last part of the basic setting and sometimes there is difficulty getting down to the last step (1 of 5). If you don't get down to 1, it will still work but might be "jerky" as you describe. At the of best times, like most automated gearboxes, the system is not smooth at slow speed so you just adapt to it. Setting the clutch voltage lower MIGHT help.

RAB
 
I spoke too soon. The little ******* left me by the side of the road! The gearchanges where getting sloppier and sloppier until after an intersection it wouldn't change up from 1st and then it stopped responding to the accelerator. Tried restarting it but it wouldn't start up after I shut it down. Had to call the towtruck. Hopefully my mechanic can confirm by some fault code if it's the slave cylinder that is borked now.
 
Another thing to check is the rubber "bung" on top of the bellhousing. If it is missing, water may have entered and caused the clutch to seize.

RAB
 
RAB said:
Another thing to check is the rubber "bung" on top of the bellhousing. If it is missing, water may have entered and caused the clutch to seize.

RAB
Click to expand...

You mean the parts 020301132 and 020301129B?

My mechanic said that the car reported some error codes about illogical clutch sensor readings and faulty gear actuator sensor reading. Can't remember what they were exactly, though. Any more tips I could relay to him?
 
Very unusual for both actuators to fail at once. I wouldn't have thought it possible! Are you sure there's not a wiring problem?

RAB
 
I don't know. The codes didn't come up again after they were cleared. He'll run basic setting and see where it won't get any further.
 
Check all the connectors between actuators and hydraulic unit. There are two connectors under the hydraulic unit that connect the actuator loom to the hydraulic unit as well as the 7 connectors to the actuators. I've just spent most of the weekend sorting out my wife's 3L which had a problem with reverse gear. The cause was eventually found to be an oily connector to the reversing switch!

RAB
 
On one of my Lupo 3Ls I have been having a red flashing P symbol in the centre console just above the handbrake (no beeps). This only flashes when I stop the car with the gear selector in Stop. If I stop by moving the selector to Stop this red P light flashes. If I put the car in N and turn off with the key, no flashes, but once I then move the selector to Stop, it flashes. It is as though it is warning me to put the handbrake on. However, when I apply the handbrake, the handbrake symbol lights up on the speedo, confirming handbrake on, so it is not the handbrake switch (unless there are two), but the P light still flashes. Maybe the transmission controller thinks the gearbox has not shifted into Park properly (but it has it is in gear).

I have checked the transmission fault codes, there are none, and the ABS fault codes, again none.

This strange flashing started about a year ago, and I had been ignoring it, as there were lots of genuine issues needing attention, an airbag light, rear brake shoes, plus a leak starting from the gangsteller lower seal. This month I gave the car a good going over, new brake shoes, airbag slip ring, changed the lower seal on the gangsteller, checked for leaks (none), did the basic setting which threw up a faulty potentiometer on the gangsteller (replaced the potentiometer, basic setting again). Also just replaced an inner driveshaft triple joint which had play in it. It was running with all these faults, and now they are fixed the flashing remains. It does drive very nicely now, I can tell the difference, but it won't pass a Swiss inspection with the flashing P... Any ideas please?
 
What you describe is normal except that the red 'P' light should go out with the handbrake on. It's not just a switch though as the flashing should time out after a minute or two if the handbrake is not applied. Faulty relay or similar?

RAB
 
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