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348 348 gearbox behavior

Discussion in '348/355' started by raoulfilippi, Jan 13, 2020.

  1. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi
    Hi guys, lately the gearbox of my 348 is showing a strange behavior. When i pass from second to third gear i receive two responses. If I release the second, pass to neutral and then i insert the third gear all is working fine, but if i try to change in “sport” mode, passing directly in a unique movement between the two gears, the inserption of the third gear seems bit “harder and skidy to insert”. (Difficult to explain in simple words)
    The opposite action, I mean from third to second, is ok, and also the movement from fourth to third gear appears fine. Anyone of you has noticed the same mechanical backlash? what could it be?Bearings?
    Thx for your opinion


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  2. ernie

    ernie Two Time F1 World Champ
    Owner Lifetime Rossa

    Nov 19, 2001
    21,910
    The Brickyard
    Full Name:
    The Bad Guy
    I would check the condition of the bearings on the main and lay shaft, also the condition of the ring nuts, especially on the gearbox oil pump side of the shaft.
     
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  3. Ferrarium

    Ferrarium Formula 3

    Jul 28, 2018
    1,681
    Central NJ
    Full Name:
    Eric
    I know the ring nut under the TOB, but the one you mention, is it behind an access plate accessible with wheel off?
     
  4. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi

    thanks for the suggestion, I'm gonna ask to the mechanic to check it out.
    Is it an operation that suppose to just disconnect the gearbox, or should it be totally opened?


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  5. pnicholasen

    pnicholasen Formula 3

    Jan 14, 2011
    1,299
    South of Philly
    Full Name:
    Paul Nicholasen
    Ernie knows way more about this than me, but if after checking out his recommendations, you find nothing wrong, just for laughs, try lubricating your shift cables if that's never been done:



    Unlikely to help in this situation, but it won't hurt, and it will ensure you double check the nuts, bolts and joints where the cables attach to the shift lever and transmission mechanisms.

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  6. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi

    Thanks a lot. This will be surely done. If possible I’d like to know if the bearings to be controlled are inside the box or if can be inspected just by loosen the shafts from the rest of the structure.


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  7. Rupp3r

    Rupp3r Karting

    Aug 26, 2016
    141
    France
    These bearings are on the passenger side of the gearbox.
    You have to remove the transmission and the side cover.
    But then you only see a little bit of the outer balls of the bearing and if you want to really inspect them you have to remove them.
    To remove the bearings you only need to remove their casing on the side and the rest of the gearbox is not touched.
    But your symptoms make me think more about a synchro ring or adjustment issue?
    A bearing would be more like a constant noise?
     
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  8. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi
    Hi, thanks. Probably is how you have said. At the end I won’t be surprised in will be a synchro ring to replace.
    This means open the box (with the price increasing indeed, not for the ring itself but for the price of the labour)
    If confirmed, in September I’ll proceed to dismount the box and change the ring.
    In the meanwhile the car is still usable whit the proper care.


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  9. Ferrarium

    Ferrarium Formula 3

    Jul 28, 2018
    1,681
    Central NJ
    Full Name:
    Eric
  10. steved033

    steved033 Formula 3
    Silver Subscribed Owner

    Apr 12, 2017
    2,126
    Atlanta, GA
    Full Name:
    Steve D.
  11. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi
    Don’t understand what’s the problem with the filter. You mean just for the removal?


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  12. steved033

    steved033 Formula 3
    Silver Subscribed Owner

    Apr 12, 2017
    2,126
    Atlanta, GA
    Full Name:
    Steve D.
    most filters of any sort have some maintenance schedule. I can't find any information on the gearbox filter.

    sjd
     
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  13. Rupp3r

    Rupp3r Karting

    Aug 26, 2016
    141
    France
    The gearbox filter is a plastic bag filter and I don't think it needs to be changed, just cleaned when the oil pump casing is opened since its aim is only to catch metal chips.
    Anyway it is not anymore produced and really hard to find..
     
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  14. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi
    Ok, gotcha. You are referring to the magnetic trap,right?


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  15. Rupp3r

    Rupp3r Karting

    Aug 26, 2016
    141
    France
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  16. ernie

    ernie Two Time F1 World Champ
    Owner Lifetime Rossa

    Nov 19, 2001
    21,910
    The Brickyard
    Full Name:
    The Bad Guy
    In order to get to the ring nuts and outer bearings you will need to remove the gearbox. Run a search of the archives to see the damage that gets done to the ball bearing cages.
     
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  17. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi
    Thanks a lot


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  18. raoulfilippi

    raoulfilippi Karting

    Sep 28, 2018
    61
    Bologna-Italy
    Full Name:
    Raoul Filippi
  19. Rupp3r

    Rupp3r Karting

    Aug 26, 2016
    141
    France
    If you inspect the oil pump side bearing then you will have the oil filter in your hand like on my picture.
    I don't know if it will help a lot.
    I found some aluminium chips in my filter but a part from that my gearbox was perfect and found others example like mine speaking about machining chips.
     

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