Haldex issues symptoms & diagnosis fixes?

[Octabus]

So, it would appear that the "full" service history I bought it with did mention Haldex oil changes....

 

.. only a reminder that they were due! - gotta love second hand car dealers!

 

unfortunately it appears that I am having signs of transmission wind up (those having hilux/landy with diff lock will know)

 

Symptoms:

slight juddering/resistance to roll on full lock, typically parking or pulling out of a tight junction, the car feels almost "heavy" 

rear tyres showing feathering across the tread (feel sharp when you run your hand one way over them)

The traction control light flicked on briefly round a slightly bumpy bend

25mpg on a steady 25mile A road run suggests there's some drive train loss... 

 

Doesn't always do it, (didn't on the test drive either - typical)

 

Diagnosis:

the juddering and hesitation is because all 4 wheels are trying to turn at the same rate, which isn't possible when you are turning tightly, as the wheels on the outside turn more than on the inside (think of a rainbow - red is bigger than violet!) the tyres are forced to slip to release the tension in the transmission, which in turn shows the odd wear pattern.

the traction control (ESP in my case) monitors the turn rate of all four wheels, and will let you know if it smells something fishy!

 

Fixes:

Oil and filter change ASAP - is it too late? I understand you need a silicone cartridge type tube, with 375ml of the magic Haldex oil? 

How do I determine part numbers/spec required for my vehicle (being a shady Yorkshireman and not really wanting to/having time to visit the main dealers)

 

Something about an earth strap??

 

Wet clutch/dry clutch.. replaceable parts?

 

gallon of petrol and an insurance claim?*

 

*This is not a serious suggestion - petrol is too expensive!

[snow_muncher]

Sounds like your rear transaxle differiential, as opposed to the haldex clutch

 

It has its own gear oil, separate to the hydraulic oil in the clutchpack

[Octabus]

Surely a rear diff would whine and slop rather than sieze up, or what landrovers normally do.. slip teeth and eject cogs through the casing? 

 

As I understand it the haldex jobby takes the place of a central diff, and the symptoms I have, to me are are like that of a 4x4 with a locked central diff (landy, or a hilux with no central diff) where drive goes equally to the front and back... the effect is that a front wheel and a rear wheel have to turn at the same rate?

 

What would be the process of elimination here?

 

Thanks

[Octabus]

so, in brief, it grumbles a bit on low speed full lock, steering feels heavy, and the back tyres are feathering inwards (sharp as you pull your hand OUT from the wheel arch)

 

Snow muncher, are your rear tyres wearing in a similar way? this may even be normal characteristics?!!

 

Thanks in advance

[snow_muncher]

haldex cann't lock like a hilux drivetrain or  a locking open-diff

 

The haldex system uses an eletric motor to pressurise the clutchpack, it doesn't lock the diff, but changes the lockup ratio

 

The clutch plates can wear out, but iirc this leads to lack of power transfer rather than locking up

 

Persuading the haldex unit into full pressurisation is a known upgrade - for example Powertrac Insert, SQS Regulator, Blue  Haldex, etc - even if the central diff is full binded up, the rear axle  diff is there to handling the difference in turning speed of the wheels - eg like a rwd car

[snow_muncher]

I'd get the car on a scissor type post ramp, so you can run the car with the wheels free

The controller should set the clutch to full pressure

You can then test disengagement by gently pulling on the handbrake

Under VAG software the haldex system should release all clutch pressure on any form of braking

[missingmyvrs]

As above

[karlbar2k]

Just a quick thought.  when was the last time it was on 4 wheel tracking? something like a Hunter? I had feathering and odd wear on the rear of mine and it turned out that it was way out on the back.  

I had the rear diff oil changed at the same time as the haldex (only because we dropped the wrong plug ) I thought it was supposed to be life of the car though?

 

edit: you can also test by pulling the fuse to disable the haldex - forget which one but when I had other issues (slight knocking?) with mine pulling the fuse  seemed to get rid.

Edited 21 May, 2014 by karlbar2k

[James I]

My two penny's worth..

 

 My Golf had similar symptoms albeit worse than you describe. The Golf had permanent all wheel drive and would grind and hop when turning on full lock, I decided to buy a secondhand rear diff/haldex off ebay, as it happened I dropped on a full S3 rear subframe with drive shafts and diff/haldex, I changed the lot and problem solved.

 

 This lead me to strip the old diff/haldex unit apart, I couldn't find anything wrong with the diff so I assumed the haldex was at fault.

 

You can see what I did here.

[fireblade]

Has the oil been changed on the haldex? Easy job, only takes a litre and takes about 20 mins

[Octabus]

Thanks  everyone, I have had the haldex oil and filter changed, and can confirm it feels much better - but wasn't an instant fix. definitely better in carparks and at tight junctions, only my right foot and a lack of patience give any resistance.

 

as for the tyre wear, I'm going to have to monitor that, but rear wheel tracking could be worth chacking.....are they adjustable?

...also need to remember that recent wet weather, and having both power and grip does make me a little wreckless when the opportunity presents... the few perks to driving big empty roads early on a morning!