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6 speed 4WD gearbox and front diff oil change

Discussion in 'A3/S3 Forum (8L Chassis)' started by pj123, Nov 2, 2010.

  1. pj123
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    pj123 Member

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    I'm looking to change the oil in the gearbox of my 1999 s3 on 90k as the gearbox is stiff when cold and it didn't used to be.

    I've read a bit about the gearbox and the front diff being connected and the way to change the oil is by removing drain plugs from both the gearbox and the front diff and refilling through the gearbox filler only. After refilling it was suggested to go for a short drive and then top up. Is this correct? I'm worried about draining two sides of a system and only refilling one side - and then driving on it?!?!. Why not just have one drain?

    For ref the Audi Maintenance manual states:

    Oil should be G50 SAE 75w-90
    Audi only mention topping up the fluid and do not describe how to change fluid, but do specify that on the 6 speed A3 (Manual gearbox 02M) the filler plug must be renewed. Does not state this for 5 speed boxes.Tightening torque of filler plug to be 30Nm.

    Thanks in advance for any help.
    Paul
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  2. Duktor
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    Duktor Member

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    im interested in this too as plan too do mine
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  3. pj123
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    pj123 Member

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    I asked the same question to Audi and got this response

    "Filling Qty for the gearbox is 2.6 L so we will need to supply 3L cost £45.36 inc vat. ( I only have part numbers, no spec) There is no separate oil listed for the angle drive on the gearbox, it may be it shares the oil from the box, or it could be a sealed unit. "

    Hoping to change the oil this weekend so anyone know the answer?
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  4. Duktor
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    Duktor Member

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    a how to would be very good on this one pj so get snapping whilst u do the job m8
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  5. pj123
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    pj123 Member

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    Happy to do a 'how to', but I really want to know the proper way to fill the front diff before i drain it. From the TT forums people 'go for drive to fill the diff from the gearbox'. Does this sound right?
    #5
  6. Duktor
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    Duktor Member

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    dunno m8 your asking the wrong guy but im sure someone could pipe in thats done it b4 , if not you could try doing a help post and link it to this thread !
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  7. tompearson
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    tompearson It's all in bits

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    This is probably what you want....

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  8. Duktor
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    Duktor Member

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  9. pj123
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    pj123 Member

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    Thanks Tom, if the rest of that guide is available could you post?

    Can someone tell me how to post attachments to do a 'how to'?
    #9
  10. Duktor
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    Duktor Member

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    upload your pics to photobucket then paste the link into your how to, there are 4 seperate codes cant rem which one is the correct one but a bit of trial and error and you will soon get the jist of it
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  11. quinnj2
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    quinnj2 Member

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    If you want to properly change the oil you will need to drain the bevel box as well as the actual gearbox. Just draining the gearbox without doing the bevel box leaves around 1/4 to 1/2 a litre of old oil.

    I used about 2.6l of this, Mobilube 1 SHC 75W-90 fully synthetic, supreme performance commercial gear oil. Also used the same stuff for the rear diff which I think takes about a litre. I never renewed any plugs but did give them a good clean and check.

    I used a suction gun to fill them up to the correct quantities then checked the front after a drive by undoing the filler plug whist the car was on level ground, put some more in it and then just let it drip out until it stopped, which means it's at the lower part of the plug. All instructions are in elsawin, not got it loaded at mo though.

    I do this every two years and well worth doing in my opinion, just make sure the correct quantities are being used and don't overfill anything.
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  12. quinnj2
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    quinnj2 Member

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  13. quinnj2
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    quinnj2 Member

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    p.s always try and undo the filler plugs first then you can be sure you can fill her up again, the last thing you wanna do is drain it all out then realising you can't get the filler plug out or it's been over tightened and threaded..
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  14. Duktor
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    Duktor Member

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    thanks for the link m8 let us know how u get on pj any luck on finding a how too for the rear diff yet
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  15. quinnj2
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    quinnj2 Member

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  16. pj123
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    pj123 Member

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    As far as I can see this guy is now driving round with an underfilled gearbox!!

    I will do these things differently:
    1) Drive the car till its warm before draining the oil
    2) After filling for the first time go for a 2 minute drive fo fill the diff from the gearbox then top up the gearbox.
    3) Just to be safe will probably re check levels after a longer drive.

    oh and use new gearbox plugs.
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    spencer-s3 likes this.
  17. quinnj2
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    quinnj2 Member

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    Yeah doing warmup is a defo must, When I did mine I was anal and also checked the amount that came out in the first place. If you drain the bevel box then yes you need to drive it to then fill it back up and then top up the gearbox until it drips out the filler hole.

    As long as the plugs are in good condition and are clean I see no point in changing them. The only one I have ever changed is the haldex drain plug.
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  18. Duktor
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    Duktor Member

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    all good advice anyway guys , what would be the reason to change the plugs if the threads and socket hole was ok it should be fine reckon they might be known as stubborn to remove which might lead to damage !
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  19. pj123
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    pj123 Member

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    I can only presume the plugs and/ or the gearbox are made from a different material to the other A3's and that is why the manual only specifies the plug to be replaced on the 6 speed box. Maybe the plug crushes slightly to form a seal similar to a sump plug washer. Just guessing, it may become clear when I take the plug out.
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  20. pj123
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    pj123 Member

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    So I changed the gearbox oil this weekend and there is a significant difference. When driven from cold there is now less/ almost no crunch from first and second which i was having a problem with, gear changes generally feel smoother and when backing off the throttle there is less vibration back through the gear lever so glad I changed it. The oil that came out was partly discoloured (11 years, 90k) but still had a hint of the same colour as the new oil. I used OEM oil.

    Carried it all out using the tips highlighted above except for
    - Didn't use new filler or drain plugs, the ones on the car were fine. (although looking at the plugs on the rear diff i will definitely replace those when i get around to it as they are seriously corroded)
    - I bought a Draper Suction Gun, but would not use one again. Not sure if i had old stock but the rubber seal on the plunger seemed too hard and did not seal. As soon as it was upside down it leaked oil out of the breather hole at the back of it. If I was to do it again i would use a simple length of clear hose and a funnel. I will use this method for the rear diff as it guarantees getting all of the oil in and saves the mess of refilling a 500ml gun with 3 litres of oil. Basically it was messy!

    The question about how the diff gets filled from the gearbox has been answered by Tuffty. Pic below from Tuffty shows diff and gearbox and the small holes with green seals allow oil to pass between the gearbox and the diff...

    [​IMG]

    and this was the amount of metal stuck to the metallic sump plug on the diff

    [​IMG]
    #20
  21. Sam_
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    Sam_ Down under

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    Bringing back a blast from the past as I'm planning on doing a fluid change of box, rear diff and haldex in one hit...

    How do you drain the transfer box then? Same drain plug as the box?
    #21
  22. TDIQ
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    TDIQ 8L > 8P > 8V

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  23. Empty
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    Empty New Member

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    Any oone used Fuchs Titan Race SYN 5 75w90 oil in gearbox ? Any feedback im thinking about change oil next month .
    Thanks in advance
    #23
  24. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Gearbox oil should be 75w90 semi or fully synth but needs to be GL-4 spec not GL-5 spec as GL-5 spec can damage the syncros


    <tuffty/>
    #24
  25. Sham101
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    Sham101 Member

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  26. Mrt4x4
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    Mrt4x4 Member

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    Hi guys,

    I purchased some fuchs tintan sintofluid sae 75w 80 gearbox oil for a different car, then sold it, will this be ok for bam225 6speed box

    Opie oils said it was fine but thought id ask here too
    #26
  27. Drysdaro
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    Drysdaro New Member

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    Sorry to jump in on an old thread, but is there a separate drain plug for the transfer box in addition to the drain for the main gearbox?

    Cheers.
    #27
  28. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Yes... bottom left of the end of the transfer box as you are looking at the inner CV

    <tuffty/>
    #28
  29. Drysdaro
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    Drysdaro New Member

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    Cheers tuffty!
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  30. Gazwould
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    Gazwould Active Member

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    I've got this in my 6 speed FRK gearbox, it is a GL5 but modern ones don't attack the yellow metals. Some GL5 are too slippery and are more suited to diffs.

    It seems VAG 5 speeds prefer 75W 90 and 6 speed 75W 80 .

    With the B8 chassis A4 2.0 TDI oem is 75W 90 but due to the amount that are experiencing poor cold shifts have produced a oem 75W 80 .

    It should of had this from new.
    #30

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