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Rear diff / haldex

Discussion in 'A3/S3 Forum (8L Chassis)' started by jonny87, Jan 17, 2010.

  1. jonny87
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    jonny87 Active Member

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    so whilst servicing the car today was poking around underneath to see if i could locate the haldex drain plug, all i could see were two cap head style plugs on what i would assume to be the rear diff, one on the side about half way up the casing and one on the bottom

    two questions;
    if i am correct in thinking that this is the rear diff and not the haldex what are the service intervals for it, as i want to make sure i cover as much as possible servicing wise

    secondly, where is the haldex drain plug located in relation to the above?

    thanks in advance
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  2. Lemon S3
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    Lemon S3 Alex

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  3. jonny87
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    jonny87 Active Member

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    yer ive seen that picture before, its not very clear, like i said i couldnt find it anywhere, was under there for ten mins searching

    im jealous of how clean that dudes golf is underneath in the video!!
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  4. Lemon S3
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    Lemon S3 Alex

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    I found it straight away after seeing that picture, it's just a small plug on the bottom of the haldex with a 5mm allen key insert. Still unsure about the filter though but think I saw it, looks like an absolute bugger to get to.
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  5. jonny87
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    jonny87 Active Member

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    hmmmm, i obviously missed it, but yer it does all look a bit tight under there, might just bite the bullet and pay someone to do it
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  6. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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  7. Lemon S3
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    Lemon S3 Alex

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    Drain plug...
    [​IMG]
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  8. jonny87
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    jonny87 Active Member

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    yer i totally missed that one, mind you mine aint so clean underneath lol

    i wont be doing it myself now anyway as i went to audi earlier to exchange a pollen filter (they give me the worng one)
    whilst waiting i got talking to someone behind the desk about my s3 and i thought while i was there i might aswell ask how much a haldex service would be, £156.49 was the answer, broken down into £50 parts £90ph labour £16 vat, i told him i was thinking of doing it myself which would cost me £60-80 for the service kit and the tool

    then he turned round and said well if we could do it for £90 would you be a happy chappy?

    hell yeah i would be was my response :) so got it booked in for weds morning, loving it!
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  9. Lemon S3
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    Lemon S3 Alex

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    Yeah I wish mine was that clean too, had to scrape off an inch or grime before I could see the plug lol.

    I'd rather do it myself than spend £156 for someone else to do it.
    You can get the service kit and filter tool on ebay for about £30.
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  10. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I bought the tool off ebay for £25 then filter and oil was about another £25. Thing is I've now got the tool so can do it whenever it needs doing for just £25 now.

    Good work on striking a deal at the dealers.
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  11. Lemon S3
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    Lemon S3 Alex

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    I was just about to correct myself, looked on ebay again and saw the service tool is sold seperately for another £30. Like you said once you have it, you don't need to buy it again, just oil n filter.
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  12. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    I paid £17+vat for mine from GSF :)

    <tuffty/>
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  13. Westy
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    Westy Double Dark Side! Diesel & 8P

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    The rear diff oil change is a bit more difficult I think. I got an Audi specialist to do it for me when they did my service. I think they had a bag of diff oil hanging from a pole (a little like a hospital drip) and let it run down a pipe into the rear diff.
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  14. Lemon S3
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    Lemon S3 Alex

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    You get the oil in a tube that can fit into a mastik gun and put it in the same way the oil comes out but you have to be quick when putting the plug back in so you don't lose too much oil.


    EDIT: 100th post! :arco:
    Last edited: Jan 18, 2010
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  15. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I'm talking about the diff oil change not the haldex oil change, 2 different things.
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  16. jonny87
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    jonny87 Active Member

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    yer i was really taken aback that he knocked close on £70 off just like that, i couldnt refuse really, i could well be the only person in history to get a discount at the dealers lol

    westle: i was looking at the rear diff yesterday, looks pretty easy to me, way easier than the haldex from what i saw, got a drain hole and a refill hole, refill hole is a bit tight but if you had something similar to the haldex oil syringe thingy would be easy peasy, this may well be next on my list

    even if they do use a sort of drip system to fill up the diff with new oil, its nothing that you couldnt knock up yourself really, length of hose and a funnel, may have to take off the rear wheel to get a better angle for the oil to go down at
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  17. Lemon S3
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    Lemon S3 Alex

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    :sorry:
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  18. jonny87
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    jonny87 Active Member

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    haha get told!!
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  19. Westy
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    Westy Double Dark Side! Diesel & 8P

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    Dont worry it comes up all the time. The Haldex oil and filter are meant to be serviced. There is no service interval for the rear diff but I got mine done along with my gearbox oil because my car is now at 115K miles. Next time you get a service ask them to do the rear diff (not the haldex) and it wont cost much extra to do.

    Jonny87 I think my Audi mech accessed the rear diff fillup plug via the boot compartment somehow!
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  20. jonny87
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    jonny87 Active Member

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    :wtf: how the f did they do that?

    i wonder if theres a blanking plug somewhere in the boot pan allowing access, could be worth investigating me thinks!!
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  21. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I didn't see it as I had the service done while I was at work. All I know is that my boot needed a bit more force to shut (almost like the catch had been knocked out of line slightly) after the service and my mate saw it being done out the window!
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  22. jonny87
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    jonny87 Active Member

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    hmmmmm thats weird!!

    il have a snoop around at the weekend see if i cant figure something out as its something i would like to do
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  23. S3PEG
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    S3PEG Member

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    Trying to get your head round this lot is tough for someone with limited mechanical understanding! Can someone check that I've understood everything?!

    1) the haldex and the diff oil are 2 different things.
    2) when changing the HALDEX oil, you should also replace the filter and you need a special tool to remove this. The service kit and tool are sold on ebay but maybe cheaper from GSF or similar. HALDEX oil should be serviced at the same intervals as the car.
    3) changing the DIFF oil should be a little easier than the haldex oil, there is no filter involved and you can pretty much use the same syringe/mastic gun setup to put in new oil although there are no service intervals.
    4) Gearbox oil is different again to the haldex and diff oil. Not sure about service intervals.

    And can somebody (preferably someone who's done the oil changes) confirm the amount AND type of oil required for each change?

    Thanks.
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  24. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Yes... Haldex is a hydraulicly operated clutch that engages the rotation of the prop shaft to the roation of the rear diff... much like the clutch up front does between the engine and gearbox

    Audi suggests Haldex oil every 20k and Haldex filter every 40k... for the effort and peace of mind it gives then I do both every 20k... If you know you are going to keep the car long enough to rack up the mileage then its worth the extra IMO...

    The drain and filler plugs can become encrusted and could be a bugger to remove... I bought new ones from Audi to replace mine... magnetic one at the bottom (drian) and a replacement for the filler one... clean them round with a small wire brush and apply penatrating fluid allowing it to soak for a while... uses a 17mm allen headed removal tool that I fashioned from a short 17mm headed bolt and nuts to lock it together... I then used a spanner to undo but any 17mm allen type sump tool should do the same thing.

    I used a 1ltr squeeze bottle (as this is what it normally comes in) to fill with and had an additional 4ltr of gearbox oil that I used to fill the squeeze bottle up with as it ran out until the diff was full. Its full when the level is just below (although I think I let it run out tbh) the filler hole... I used a bit of welding rod bent round to act as a 'dipstick'

    Yes, very different... Haldex oil is hydraulic fluid, diff oil is gearbox oil...

    Audi don't specify a service interval for the diff or the gearbox for that matter but its 20k for Haldex oil and 40k for Haldex filter... as said before, I do both at the same time...

    The Haldex oil comes in tube to be used in a caulking gun, I used a bit of silicon tube and cut the nozzle in half joining it with the silicon... this is because you have to fill the Haldex from underneath!!??!! and if you are doing this on axle stands or ramps then you won't get the caulking gun at the right angle to do it....

    For the diff use 75W90 semi synthetic gear oil... I bought a 1ltr squeeze bottle and a 4ltr container of the stuff so I could do both the gearbox and the diff... I can't remember exactly how much each used if I was honest but I do have a bit left in my 4ltr bottle and thast was filling both gearbox and rear diff of course.

    You are welcome :)

    <tuffty/>
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