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Centre Diff/Transfer Box

Discussion in 'A4/S4 forum(B5 Chassis)' started by Z82, Jun 28, 2009.

  1. Z82
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    Z82 Member

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    [Jun 28, 2009]
    Bear with me as Im not fully clued up on the quattro IV system.

    I've got a problem with my car (more info here: http://www.audi-sport.net/vb/showthread.php?t=72205) and Im trying to gain a little more knowledge to get me by.

    1. does anyone have a diagram on the quattro IV system on a B5 that shows all components?

    2. Is the Centre Diff/Transfer Box part of the gear box or is it a seperate item?

    3. If this is my problem do you think I'll need to replace rear diff too?

    4. If I decide to run the car to death, is there any safety issues and what is likely to happen in doing so?



    TIA
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  3. Z82
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    Z82 Member

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    [Jul 4, 2009]
    OK after a LOT of hunting I've managed to answer my first 2 questions myself but it would be good if someone could help me with the last 2 please.

    [​IMG]

    It is a seperate component from the gear box but comes as one item from Audi, I can only locate an upgraded diff on the net so far.

    [​IMG]
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  4. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Jul 4, 2009]
    A torsion diff is part of the box, i know it can be dropped out seperatley to be tweaked with washers to alter the power distribution. But it is not a seperate bolt on unit, its housed within.

    The rear diff is completly seperate to the rest of the drive train, no reason to assume that damage has spread to this unit. Usually it's plenty audible !!

    I cannot imagine how a noisey centre diff will hurt anything, but if it were to go, you would either lose drive or it could possibly lock solid, thos the first option would be more likely IMHO

    Shame you don't live a bit closer Mark, i would gladly have taken a listen/peak for ya
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  5. Z82
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    Z82 Member

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    [Jul 4, 2009]
    So it does look like Im looking at a complete box then but the one on ebay the guy said the diff wasnt part of the sale.

    Its a pain being up here as there is not many that are familiar with quattro's :(
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  6. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Jul 4, 2009]
    He is more than likely thinking of the rear diff, do you have a pic mate? If it has a flange on each side and one at the rear, it's complete
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  7. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 4, 2009]
    If you purchase a used quattro gearbox, you will get the centre diff with it. No-one is going to strip the tranny down and remove the diff.

    I still cannot fathom how the gearbox itself can make a clicking noise. The centre diff doesnt have anything within it that can click. A torsen only has gears inside, and gears cant really click. If they were slipping it would be grinding and sound fecking awful. Otherwise it would whine like a streight cut gearbox.
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  8. Z82
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    Z82 Member

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    [Jul 4, 2009]
    No no pic of the box he just had a pic of the car thats why I emailed him.

    The Audi specialist I took it too reckoned it was the centre diff but wasnt 100% sure however he said he put it on the ramps and the wheels moved too freely for being a quattro?? :-/
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  9. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Jul 4, 2009]
    moved too freely? Thats a new one. Anyway to record said noise ?
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  10. Z82
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    Z82 Member

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    [Jul 5, 2009]
    Yup "moved too freely". He said a quattro wheel should have some tension in them when turning by hand and mine didn't.

    I'll try and record the noise but it will be hard to get it audible with it only happening when driving.
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  11. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

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    [Jul 6, 2009]
    Centre bearing on the prop maybe? I wasn't sure if quattys had them, but viewing Sienas pics its obvious that they do
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  12. Z82
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    Z82 Member

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    [Jul 7, 2009]
    Hmm thats a possability.

    Recording is pretty **** Im afraid.

    You can hear the noise at 1:14, 1:47, 2:45 & 2:55. At 3:39 you hear the judder from the rear too.

    http://www.nosmodified.com/images/temp/Sound clip 02.wav
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  13. dieselfitter251
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    dieselfitter251 Blow ma own trumpet?

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    [Jul 7, 2009]
    Centre bearing on the prop maybe? I wasn't sure if quattys had them, but viewing Sienas pics its obvious that they do

    The centre bearing on my prop shaft was an advisory at the last MoT. The guy showed it to me when the car was up, with the bearing on it's way out there's verticle movement on the shaft, quite a bit on fact but no noticable noise when the vehicles moving. The only thing I think may be attributed to this is when turning tightly at slow speeds there's a slight grumbling noise, coming through the car.
    The judder you've got may be rear diff bushes and may be the centre bearing on the prop shaft. Before the rear diff bushes were done on mine I had a slight knock and judder and now they've gone. I'd look at the 'easier' servicable itmes first, if you haven't already.
    One thing I have found out is that the prop shaft isn't really serviceable. The centre bearing doesn't come off. I'm sure you could strip it all down or send it off to a specialist but I think you'd also have concerns over whether it came back properly balanced etc. I've sourced replacement props from breakers from £120 - £200.
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  14. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 8, 2009]
    My dads old transits centre prop bearing was shot for about 5 years.

    Every MOT it was listed as an advisory, but it didnt actually have any noticable signs or noises so it was never fixed.

    Having listened to that sound clip i'm a bit stumped. Sounds very odd, but i'm still not sure its a gearbox fault. The clip isnt great and my laptop doesnt go very loud, but it sounds almost like a soft rattle or perhaps a rapid squeaking rather than clicking?

    I'd remove the rear propshaft and check all the joints on it for wear/binding before going any further. You really REALLY dont want a prop letting go.
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  15. Siena
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    Siena Active Member

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    [Jul 8, 2009]
    By sheer coincidence, a customer of mine has just had his torsen diff let go, in his 1998 B5 2,8 Avant quattro.

    Stripped it down yesterday, and there's a hole the size of a garden pea in the casing, so something's obviously escaped, probably a ball bearing.

    The centre bearing on his propshaft is also non-existent, so that would have killed the torsen diff anyway.

    If a propshaft lets go, gosh. You don't want to be in that car - it smashes through the floor, and anything it hits - even a cast iron block will be pulverised.

    That slight scrape-scrape-rattle-rattle sounds very much like a worn propshaft. I had mine fail too, on my old RS2-engined Coupe quattro, on the way to Silverstone, back in 1998. That noise had been there for a while, but I couldn't work out what it was.

    It destroyed my centre differential - smashed the bearings, and tore the oil seal out, the back of the car was covered in oil spray.
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  16. Z82
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    Z82 Member

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    [Jul 8, 2009]
    OK cool guys youre all giving me a few options to look at. Looks like I'll be busy this weekend.

    I'll also try and get a better recording of the noise too.
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  17. dieselfitter251
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    dieselfitter251 Blow ma own trumpet?

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    [Jul 9, 2009]
    I for one wiill be very interested in your findings!
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  18. Z82
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    Z82 Member

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    [Jul 16, 2009]
    Well...
    Sparks (fellow ASN member) popped over tonight to give me a hand as I was not sure what I was looking for.

    The prop is moving at the centre diff but we reckong the play is in the diff rather than the prop its self.

    Looks like I'll need to get her in to a garage so I can start stripping her down to get the prop off then take it from there :(
    #17
  19. docurley
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    docurley Moderator Staff Member Moderator

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    [Jul 16, 2009]
    Well I have the Rear diff and the prop is you find it's any of them.
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  20. Z82
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    Z82 Member

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    [Jul 16, 2009]
    Thanks Doc but the 1.8tq rear diff & prop are different from the 2.6q as I found out tonight
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  21. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 16, 2009]
    different how?

    assuming the tranny is the same length, you should just be able to fit the complete 1.8TQ setup...
    #20
  22. Z82
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    Z82 Member

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    [Jul 17, 2009]
    I beleive the 1.8tq prop is 2 piece? Mine looks like its 1 piece probably about 1m long.
    Its very hard to see as exhaust runs directly below it. My rear diff looks pretty damn long too, maybe over 1m in length but this may also be the case on the 1.8tq?
    #21
  23. Siena
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    Siena Active Member

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    [Jul 17, 2009]
    I,8TQ propshaft is the same length as 2,6Q, 2-piece.
    1,8TQ rear differential is the same length as 2,6Q.

    Only issue with the 1,8TQ differential is the final drive ratio - 3,89:1 as opposed to the 4,11:1 in the 2,6Q.
    #22
  24. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 17, 2009]
    ah :(

    So the 1.8TQ prop will fit, but the rear diff would only work if you also used the TQ gearbox.
    #23
  25. Siena
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    Siena Active Member

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  26. jcb
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    jcb Active Member VCDS Map User

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    [Jul 17, 2009]
    off topic but anyone happen to have a breakdown of the gear ratios and final drives of the B5 quattro range? can't find much on google
    #25
  27. docurley
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    docurley Moderator Staff Member Moderator

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    [Jul 17, 2009]
    This any good

    [​IMG]
    #26
  28. Z82
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    Z82 Member

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    [Jul 17, 2009]
    Thanks for clearing that up guys :)
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