My Bora's first trip to the doctor

[djorkboy]

No that's just the sample they gave me. They didn't mention how much fluid came out, but I will remember to ask them when I take the car back on Monday.

The mechanic told me that the car is marginally drivable and as he trusts my judgement to be able to tell when something is wrong he feels comfortable giving me the car back to me so I picked it up yesterday.

But on the drive home it was clear the noise hasn't lessened much by changing the fluid so I am going to take it straight back on Monday and have him pull the diff out and send it off to the reconditioning place to see how much it will cost. In the meantime both me and the mechanic are looking for good second hand units in case the cost of reconditioning is stratospheric.

[Manaz]

....but, my mechanic says he called Volkswagen to find out what the service interval is for diff fluid in a Bora 4motion and he was told it is a life of unit thing and should never need replacing as a routine servicing thing, so if that really is the case, why did the fluid get changed in mid-2010?

There are two fluids related to the rear diff of a 4Mo:

1. Diff oil itself. As noted, the diff is meant to be a "sealed for life" affair.
2. Haldex fluid. Different kettle of fish - this is used by the Haldex control unit to control the engagement/disengagement of the clutch packs in the rear diff (not to lubicate them). This is a service item (every 60,000km if memory serves), the parts for it (fluid and filter/plug, they both get replaced) are easily obtainable.

The people at Volkswagen your mechanic spoke to should have made this quite clear.

For what it's worth, Haldex AWD systems are also used by other European manufacturers - Volvo, Saab and Opel in Europe to start with, so they're not just specific to VWs.

[Manaz]

there is an entire diff with haldex on ebay.co.uk for 200 pounds, but how much would it cost to get it to Australia?

I actually do have a DHL account at work.....

Be aware that the rear diff from an Audi S3 (8L model) should also fit fine. I know there's been some available locally for a while (European Autotech who you've already mentioned had one for a while), so you may find one locally, but it won't be cheap as they're relatively rare over here. They're a big, heavy unit, so shipping from overseas may not be cheap either - but if you can afford to wait and can have one sent surface, you may do OK that way.

[djorkboy]

There are two fluids related to the rear diff of a 4Mo...

....The people at Volkswagen your mechanic spoke to should have made this quite clear.....

Yeah, VW were quite clear on it. At this point there is no suspicion of anything wrong with the Haldex. From the condition of the fluid that came out of the diff I think it unlikely that it was changed in early 2010, so I'm guessing the diff oil listed in the service record is a Haldex service.

Be aware that the rear diff from an Audi S3 (8L model) should also fit fine. I know there's been some available locally for a while (European Autotech who you've already mentioned had one for a while), so you may find one locally, but it won't be cheap as they're relatively rare over here. They're a big, heavy unit, so shipping from overseas may not be cheap either - but if you can afford to wait and can have one sent surface, you may do OK that way.

I took the car back to the mechanic today, he is going to pull the diff and send it off to the re-conditioners to get a price on the fix. In the meantime both myself and the mechanic will be out looking for replacements in case the re-conditioning costs too much.

At this point, given what I paid for the car, if I can keep the cost of the diff repair under $4000 I will still have a Bora that cost me less than almost any 4motion on the market today. My preference is for a re-conditioned diff, but if the cost is going to run to too much more than $3000, including labour to fit it, I will be looking for a unit from a wreck.

I'm hoping if this is the case I will be able to get a second hand unit (diff internals only, no Haldex, no casing) for under $1500, does this seem like a price that falls within the bounds of reality? Will a unit from a MkIV R32 work? What about an early TT Quattro, that is the same diff too isn't it? Would the diff ratio be the same in all these cars?

I think shipping from overseas looks at first glance like a last resort, but $320 for a complete unit from the UK leaves $1180 for shipping to Australia if my budget is $1500. If I can recruit someone in the UK to strip out the parts I need and keep the leftovers for their trouble (the one I saw on sale in the UK comes with everything including Haldex) that might help to keep shipping costs down. Maybe I could find a kind compatriot on the UKMKIV forum who would be willing to help me out in return for some free parts?

[Manaz]

Will a unit from a MkIV R32 work? What about an early TT Quattro, that is the same diff too isn't it? Would the diff ratio be the same in all these cars?

Yes, yes and yes. All the same.

[Coralon]

I believe the 8L A3/S3 diff will also fit as it is the same chassis, haldex etc. If you are looking to source overseas then you also have the option of any mkIV 4motion golf.

[djorkboy]

So the latest in my saga...

I have yet to hear back from my mechanic on what the cost for diff reconditioning will be. He says the place he sends diffs to for reconditioning is busy and should be able to get me some info by Tuesday or Wednesday this week.

I have located a second hand diff for sale, it is from a low mileage (25k, not sure if that is miles or kms) V6 Golf 4motion from the UK. The diff was imported to Australia and the current owner says it has been stored for 8 years.

So if a diff sits for 8 years unused (filled with fluid) will it deteriorate? It looks to be in good condition externally.

[grtuned]

Is it still filled with oil?? if so and if it has not been rotated there's a chance half of crown wheel might be rusty. You would have to flip it let it sit then rotate it and see how backlash feel's, Also seals will need to be checked, As for Haldex condition who knows???
Either way your taking a risk no matter how you purchase unless you get it from sydney and have the option to take it back.
Tough call!!!!

[djorkboy]

well, the slow trickle of news about my diff continues.

The culprit is definitely hardened bearings in the diff, which is really relatively good news, it means there has been no catastrophic failure of more expensive diff parts. At this point the diff guy is still picking through to make sure there is no damage on the other parts of the diff, he did mention there is a 'harshness' of some sort somewhere else in the diff and he is hunting around to find the cause of it.

So I should know by Monday what the final cost will be and when I can have my car back.

I have been careful not to push my mechanic too hard on this as he is trying to be as thorough as possible and only replace the parts the really need to be replaced while at the same time making sure the diff is fixed properly the first time. It really helps to have a mechanic you can trust.

[djorkboy]

Finally got the full results. The diff recondition is going to cost me $2300, which is definitely a lot of money but it could have been so much worse so I am pretty happy.

All the internal bearings in the diff were trashed, everyone involved agrees that the reason for this is the bizarre VW policy that Bora 4motion rear diffs are a no-maintainance part and never need the fluid changed.

I will have my Bora back by Friday and I'm very excited.

Even with the $2300 expenditure after less than 2 months of owning the car it has still cost me less than any Bora 4motion on sale today in the country.

[Coralon]

Good to hear you got to the bottom of it and the cost isnt so bad but still a lot.

A quick google search turned up this thread which leads me to believe that after reading your story and this old one that maybe a 163~km I should propbably look at my diff oil before it too starts to whine or worse.

So much for lifetime use... or maybe lifetime is a predetermined number of years and does not take into account people will still be driving these cars 8-15 years later.

edit: And after reading this little gem I will be taking a serious look at all the 'lifetime' stuff.

[Cookie28]

I was having a look in my service manual the other day and it said that the diff oil was changed every 60k or 90k I'm pretty sure

[djorkboy]

I was having a look in my service manual the other day and it said that the diff oil was changed every 60k or 90k I'm pretty sure

Are you sure you aren't talking about the Haldex? I think mine says the Haldex viscous coupling unit needs a fluid and filter change every 60,000k but it says nothing about the diff.

About 2 weeks ago my mechanic called VW to ask them what the servicing schedule for a MkIV 4motion rear diff is and he was told that it is a 'lifetime' part and never needs a fluid change or any servicing.

[Coralon]

Just looked at the 4mo service manual and the only thing in there that even relates to a diff (but its not) is the automatic gearbox final drive oil change every 90k and as the 4mo never came with an auto... you guessed it, this is not relevent. Haldex is definately every 60k but diff is never mentioned.

After some more investigating 'lifetime' really is a legal term relating to manufacturer warranty periods to reduce total cost of ownership from new until you flog it off because you no longer have a warranty. Change your fluids lads, its malarky

[djorkboy]

Finally the day has come, I picked up the Bora this afternoon. Very happy with the results, car is smooth and quiet with no grumbling or whining from the rear.

End cost was $2077 including new bearings, diff recondition and a Haldex fluid and filter change so I'm actually pretty happy with the outcome financially.

As Coralon said, change your fluids, even the ones VW don't tell you to change.