458 Challenge Gearbox leak

Discussion in 'Challenge/GT Cars' started by Alamo Gear Head, May 1, 2019.

  1. Alamo Gear Head

    Sep 28, 2015
    We have a 2012 458 Challenge car that is leaking gear lube from a weep hole under the transmission case. It looks to be a common issue with this gear box and our local F dealership recommends replacing gear box. Other than the leak it runs perfect and no DTC's from engine or transmission. The fluid level remains full even after running a 30 minute session. We have some technicians at the track say to plug the hole to prevent it from leaking out and drain it after a run or two then check the fluid level to ensure that it remains full. Obviously there is an internal seal that is leaking, but is this detrimental to the transmission if fluid is kept full and drained periodically from this cavity. I'm using this car just for track days and not for competition. Would appreciate your feedback. Thanks
  2. windsock

    windsock Formula Junior

    Nov 29, 2006
    Beaverton Oregon
    There are two possibilities, this is a leak from a spinning shaft for the even, Odd or main shafts or it is a leak from the shift fork shafts. depending on what fluid is leaking, gear oil or clutch fluid will let you know what side of the seal is leaking, its sounds as if you are certain it is gear lube, that is actually pretty rare as it is normally the clutch fluid that is leaking. These are easily repaired although it is an extensive tear down and labor intensive.
    Plugging this hole will simply cause the fluid to transfer from the clutch side to the gear oil side or vise versa depending on which seal is leaking. clutch fluid into the gear oil is not terribly destructive but the gear oil into the clutch side will ruin clutches in very short order.
    Is it leaking consistently or only during the up and down shifts and which up and down shifts. This will determine which seal is leaking as the seals on the spinning shafts leak fairly consistently when the shaft is spinning the shift shaft seal generally only leak when the shift fork actually moves which actually occurs during the pre-selection phase as you apply or release the throttle.
  3. Joeyung

    Joeyung Karting

    Mar 9, 2011
    Can you post a picture of where it is leaking?

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