Detailed GTA Gearbox Question | FerrariChat

Detailed GTA Gearbox Question

Discussion in '456/550/575' started by TimS, Aug 27, 2024.

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  1. TimS

    TimS Rookie

    Aug 23, 2020
    23
    Full Name:
    Tim Shearman
    Really detailed GTA transmission question, has anyone else had their upper valve body apart and know if it’s correct there being no spring in the 3-4 accumulator control valve in the upper valve body - not the accumulator itself - it’s spring 305 in the image from a GM manual shown. As far as I can tell from my googling, removal of said spring would make the 2-3 shift sharper, so it might have been one of the modifications Ferrari/Riccardo made to the box? Anyone have any idea or know what was done to the GM internals more generally?

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  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,090
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    Ferrari never made any of it public even if they knew. The only person I know of who would know has passed away.
    Sounds like a cheap tuning trick that may have been employed.

    I have a good functioning unit sitting here if needed /wanted.
     
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  3. TimS

    TimS Rookie

    Aug 23, 2020
    23
    Full Name:
    Tim Shearman
    thank you….not sure what the shipping across the pond would cost but good to know, thank you!!
     
  4. FlyingHaggisRacing

    FlyingHaggisRacing Formula 3

    Jul 2, 2013
    1,377
    Forgive asking a sort of related question to Rifledriver on this thread.

    The GTA's were known for a "rattle" sound when sitting at idle in P or N.
    Put them in drive and the sound vanished.
    It wasn't the torque tube bearings and it wasn't the front bearing at the back of the engine - I remember having these replaced and it didn't cure the sound.
    It was suggested that it was the clutch in the front of the transaxle.

    Is there any definitive answer to what the cause of this rattle was, as not knowing has bugged me for years ?
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,090
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    Not too long ago I heard from England they are finding lots of the starter gears have had balance weights fall off and somehow that is causing it. It was a good source. I have one I was hoping to prove that on but owner is waiting for more reason to take it apart.
     
  6. FlyingHaggisRacing

    FlyingHaggisRacing Formula 3

    Jul 2, 2013
    1,377
    Many thanks for the reply, and here's hoping you get to investigate soon.
     

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