Leaking Gearbox Cover - help! | FerrariChat
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Leaking Gearbox Cover - help!

Discussion in '308/328' started by kurtbob, Jun 11, 2019.

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  1. kurtbob

    kurtbob Karting

    Jun 2, 2013
    64
    Augusta, GA
    Full Name:
    Kurt
    #1 kurtbob, Jun 11, 2019
    Hi folks. I just got done replacing gaskets on the oil pan and gearbox pan of my 328. I had some constant oil drips on the garage floor, and thought I would take care of some obvious leak paths. But, after sealing the pans, I still notice dripping from the gearbox cover and clutch lever (see diagrams). The parts diagram does not show a gasket on the gearbox cover. Anybody know how it is sealed, and how much work is involved in sealing it?
    Thanks!
     

    Attached Files:

  2. Brian A

    Brian A F1 Rookie

    Dec 21, 2012
    3,146
    SanFrancisco BayArea
    Full Name:
    1983 US 308 GTS QV
    #2 Brian A, Jun 11, 2019
    Be ultra extra thorough in confirming that the oil is not coming from above that flange. For example, the oil filter housing is directly above and may be the true source of the oil.

    You might put in UV dye into your gearbox oil to confirm that it is that flange that is leaking rather than engine oil leaking down from above.

    Regarding that flange itself, my understanding is that the housing is dry inside since it houses the clutch. If it is truly leaking, that means that the O-rings sealing the passages between the drop gears and the gearbox are leaking.

    As for how difficult it is to repair, others will have to comment.
     
  3. Alfer

    Alfer Formula 3
    Silver Subscribed

    Sep 4, 2007
    1,360
    NH/the Netherlands
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    Menno
    #3 Alfer, Jun 11, 2019
    Kurtbob shows the drop gear housing that is in open connection with the gearbox and indeed filled with the same gearbox oil. Actually refilling the gearbox is best done via the top of the drop gear box. The drop gearbox cover does not have a packing and should be oil tight but that means that the contact Surfaces must be 100% clean and free of any damage whilst you could use a little sealant.
     
  4. ferrariowner

    ferrariowner Formula 3

    Feb 21, 2014
    1,155
    Mansfield, TX
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    Ron
    #4 ferrariowner, Jun 11, 2019
    FWIW, Have you changed your seals on the shift rod that goes thru the oil pan. If they are leaking, you may be getting engine oil into the transmission oil which will cause a leak. I have seen this happen in the past.
    Also, leaking rear main seal may drip in that area.
     
  5. kurtbob

    kurtbob Karting

    Jun 2, 2013
    64
    Augusta, GA
    Full Name:
    Kurt
    #5 kurtbob, Jun 11, 2019
    I have not changed the shift rod seals. I will try the dye in the gearbox, to rule out (or confirm) engine oil as the leaking fluid. But, has anyone here found a leak in the gearbox cover itself?
     
  6. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    379
    #6 Hinecker, Jun 13, 2019
    Afternoon Kurt,
    I agree with all the comments stated before. IMO you have to determine "what" is leaking. Transmission oil has a peculiar smell, nothing to do with engine oil.
    You should do some more research, first cleaning the zone and afterwards seeing where the leak is coming from.
    The bell housing is sealed the engine with three "O" rings (diagram 1) and the gear cover uses sealant(diagram 2)
    My 328 had a leaking gear selector shaft inner seal. Engine crankcase pressure would build up and pump oil into the gearbox. What I noticed was that transmission oil was dripping from the transmission breather... eventually it would run all the way down the exterior of the engine and consequently on the floor.

    Just take your time and diagnose where it's leaking, instead of replacing all the seals, gaskets, O rings... That would be a hell of a job.

    Hope this helps and good luck

    John.

    BTW clutch linkage uses grease, no oil near that mechanism. If the crankshaft oil seal was leaking it would drip straight down to the bell housing.
     

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