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Crunchy up into third gear

Discussion in 'A3/S3 Forum (8L Chassis)' started by Alex C, Apr 8, 2012.

  1. Alex C
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    Alex C Well-Known Member VCDS Map User

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    [Apr 8, 2012]
    TBH I don't really want to ask the question because I am worried about the answer having had the gearbox pulled out just over a year ago for a broken shift fork.

    Anyway, I have noticed (today) that pretty much on each and every gear change up from 2nd into 3rd gear that the gears crunch. It doesn't do this on any of the other up-shifts and it doesn't do it on any of the down-shifts not even from 4th to 3rd either.

    If I up-shift from 2nd to 3rd abnormally slowly then there is no crunch, but on a normal shift it crunches.

    I have two potential causes in my head: syncro-mesh or dogbone bush?
    #1
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  3. superkarl
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    superkarl MAN OF STEEL

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    [Apr 8, 2012]
    I have the EXACT same thing.
    My dad (mechanic) says its 100% synchro.

    If I'm giving it the beans, shifting above 5k, I have to shift really slowly into third.
    #2
  4. Alex C
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    Alex C Well-Known Member VCDS Map User

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    [Apr 9, 2012]
    **** i am officially depressed
    Last edited: Apr 9, 2012
    #3
  5. jezzy
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    jezzy Member

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    [Apr 9, 2012]
    i had this problem, uprated dog bone fixed mine.
    cheap fix
    #4
  6. Alex C
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    Alex C Well-Known Member VCDS Map User

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    [Apr 9, 2012]
    thanks, guess it makes sense to change that first. I fear the worst though
    #5
  7. jojo
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    jojo Looking for Boost! Staff Member Moderator

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    [Apr 9, 2012]
    I had this in the earlier days, it only happens when shifting 2nd into 3rd at high rpm. Dogbone mount cured mine, I've not done it since, even out on the track! :racer:
    #6
  8. Alex C
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    Alex C Well-Known Member VCDS Map User

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    [Apr 9, 2012]
    ooooo! the futures looking bright! OK, I'll get a new dogbone bush asap and see if it fixes the problem.Thanks for giving me hope guys

    which dogbone bush is the one every one opts for?

    this one? Red One
    Last edited: Apr 9, 2012
    #7
  9. andrecc
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    andrecc Member

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    [Apr 9, 2012]
    diesel?
    #8
  10. Alex C
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    Alex C Well-Known Member VCDS Map User

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    [Apr 9, 2012]
    #9
  11. StaceyS3
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    StaceyS3 Well-Known Member

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    [Apr 9, 2012]
    Mine has started to do thus from 2nd to 3rd but is only at higher revs when driving it hard, but I already have uprated both the dogbone mounts underneath but I think my engine mounts are pretty shot and have got some on order so only time will tell :)
    #10
  12. superkarl
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    superkarl MAN OF STEEL

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    [Apr 9, 2012]
    hmmmmm, i know my dad said its synchro, but perhaps i could do with tightening my poly dog bone mount. maybe my engine mounts are shot too, i wouldnt be surprised.

    my gearbox is absolutely fine unless im giving it beans.

    hard to imagine a bush/mount having such an effect on gear changes
    #11
  13. S3 JOHN
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    S3 JOHN Member

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    [Apr 9, 2012]
    i fitted the yellow dog bone bush a little while ago now and it sorted out my gear crunch and i haven't found it to harsh at all . Well worth doing ! Completely transformed my car !
    #12
  14. mattyboy199
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    mattyboy199 Active Member

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    [Apr 11, 2012]
    i had a similar issue but it only occurred when the engine was at full tempreture, anyway i knew i was due a new clutch. Got a new clutch and flywheel fitted the issue disappeared.
    #13
  15. danger S3
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    danger S3 Member

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    [Oct 27, 2012]
    Hi, sorry to dig up and oldish thread but i have this problem too.
    Although it only crunches once the gearbox has warmed up so after about 30 - 45 minutes of driving.

    I've changed the gear oil, replaced the clutch/brake fluid, bled the clutch and adjusted the gear linkages.

    I was wondering if its because the viscosity of the oil when its hot is too thin. would changing the oil to something other than the oem gear oil make a difference?

    Cheers

    Ali
    #14
  16. jojo
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    jojo Looking for Boost! Staff Member Moderator

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    [Oct 27, 2012]
    Dogbone mount mate, I don't even remember the last time I crunched my gearbox since having this £20 part fitted!
    #15
  17. danger S3
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    danger S3 Member

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    [Oct 27, 2012]
    sorry i forgot to add that to the list, ive added the red dogbone powerflex one and its still doing it, although it was about a year ago i added it, could it need tightened?
    #16
  18. jojo
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    jojo Looking for Boost! Staff Member Moderator

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    [Oct 27, 2012]
    Can't answer your question, but the dogbone mount only needs to be done up as tight as you can by hand with a ratchet, then there's a specific torque setting for it bolting onto the car's baulkhead.
    #17
  19. Alex C
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    Alex C Well-Known Member VCDS Map User

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    [Oct 27, 2012]
    i fitted a dog bone mount too in the hope it would be an easy fix -- failed for me too.

    Suspect its worn synchro rings.

    I have put molyslip in the box and now double declutch and heel toe to nurse the gearbox around, its still notchy like this but doesn't crunch
    #18
  20. Gops
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    Gops 6th gear @7000rpm

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    [Oct 27, 2012]
    I had the exact problem. Sometimes its still there even with a dogbone mount but I think my engine mounts are ****. Also my xfer box is leaking at the prop so Im short on oil too! Im getting that done so time will tell. When I got the oil changed in the gearbox before, it made it feel soo smoooooth!
    #19
  21. StaceyS3
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    StaceyS3 Well-Known Member

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    [Oct 28, 2012]
    As an update to my previous post I ended up killing my box.... Pretty sure was the selector fork gone as only could select 3rd and 4th and was permanently in gear, even in the neutral position :(
    #20
  22. Munch
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    Munch Member

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    [Oct 28, 2012]
    I've got this issue, from 2nd to 3rd I get a crunch every now and again. And 1st, every now and again will just pop out of gear.
    Changed oil, fitted poly dog bone mount and still have the issue.
    Pretty sure it's synchro, so just nursing the gearbox until I can afford a new box and diff, ready for ko4 conversion late next year
    #21
  23. danger S3
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    danger S3 Member

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    [Oct 29, 2012]
    anyone reckon changing from the oem gear oil to something like Red Line MT-90 75W90 GL-4 Gear Oil would help with notchy gears and crunching from 2nd to 3rd when warm? or am i just clutching at straws
    #22
  24. colicabcadam
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    colicabcadam Guest

    [Oct 30, 2012]
    red line made a huge difference to my box, ok it was not as smooth when cold (0 degree cold) , but after about a mile it was SO much easier to change gear !!!
    #23
  25. Sam_
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    Sam_ Down under

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    [Oct 30, 2012]
    Going to chuck some redline in mine this weekend, along with a sump, pickup and oil change...
    #24

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