355 - Gearbox leak | FerrariChat

355 Gearbox leak

Discussion in '348/355' started by MikeeB355, Jun 8, 2020.

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  1. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Having just had the car serviced at a franchised dealer, I drove the car home,approximately 60 miles and parked it up. Took it out a few days later for a drive and when I got back home I noticed a slightly worrying patch of oil on the garage floor. Upon checking the car it's clearly coming from the gearbox area. The garage said there was a slight leak although it has never left any trace whatsoever and I changed the exhaust about 2 months ago and didn't notice anything then, even when the whole back end of the car was apart. They said they stopped up the level of oil. Anyway, I stripped the cover off this evening and had a better look at trying to find the cause of the leak. Am I right in thinking the first part of the casing is easy enough to removed and doesn't hold any oil inside? It's just a casing? The pumpkin?? Was going to remove that and investigate further.
    Also, when I got the fibreglass cover off there was a but and washed loose in the bottom of it, absolutely no idea where that's come from, it doesn't look like anything I removed when doing the exhaust.
    It it possible the garage over filled the gearbox oil and this is just natural wastage? I wouldn't have thought it was possible to over fill it, maybe I'm clutching at straws..
    As ever, all advice gratefully received.
    Thanks
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  2. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    Eric
    TOB or Trippe Seals. Its pretty straight forward to do it your self. Here is a link to a multiple part video tutorial.

     
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  3. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    You’re a star, thank you
     
  4. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Ok, well armed with the information from the YouTube videos I stripped the back end if the car down last night. The only difference really being the starter motor arrangement which needed to be undone but I managed to get the pumpkin off relatively easily. Happy to see the clutch assembly was still dry and clean, (does it render it useless if it gets oily?)
    The bell housing however was filthy, covered in dirty, black oil. I ordered a total of 10 seals from Hill Engineering and Maranello Parts yesterday so hopefully they'll be here some time today and I can set about changing them. Wills start by giving the area a thorough clean first though and then leave it a day to see if there are any indicators as to what was actually going on.

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  5. Ferrarium

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    (does it render it useless if it gets oily?)
    Yes it does. Pressure plate and clutch disks need to be redone or replaced. Once clutch is apart you can see. The Tob can actually crack so if that happens no seals will fix that issue, check carefully.

    Check fluid level also.

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  6. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
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    Mitchell Le
    It looks like you have a leaky slave bearing.
     
  7. Ferrarium

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    Check for cracks in it.
     
  8. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Ok, I whipped the clutch bearing and flange off this evening along with the little inspection plate and gave them all a clean. The inspection plate seal went back in easily enough, well lubricated and gently screwed back in a little at a time each side before I felt it give and then it slid the rest of the way home easily.
    The bearing seals were a different matter. Immediately obvious was one was broken, or so I thought but it seems seal 172499 is a split seal? Anyhow, only some of the replacement seals arrived today and that wasnt one of them so I cant replace it yet but 139438 did come but it won't fit. It seems that it's the wrong part and I need 176562 for that part. Should have checked beforehand that 34i parts and 355 parts aren't necessarily the same..
     
  9. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Figured it out.. I went straight with the part numbers that were called out on the video but it seems my car was a later version so uses different seals. Oh well, back on the phone in the morning
     
  10. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Ok I don't seem to be getting very far with this. I fitted the new seals and Hill Engineering bearing on the weekend and put it all back together. Bled the system and whilst it's not perfect it was 75% there so took it out for a gentle run in to check it over. Clutch worked fine, notwithstanding doing a low bite point but I was going to be getting it bled properly at a friends garage on the weekend anyway so wasnt too concerned about that.
    However,,,, upon getting back home I could smell the dreaded oily smell and noticed some black oil around the previously cleaned housing and perforated plate beneath the clutch. It wasn't as bad as before but still there's obviously something not right.
    Took the plate off this evening and there is a fair bit of fresh black oil, which makes me think a, why the hell is it so dirty and b,where the heck is it coming from??
    Going to get a fibre optic camera in there tomorrow to see if I can see the source but looks likely plans for the weekend are now going to involve getting dirty again..
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  11. yelcab

    yelcab F1 World Champ
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    Did you change any of the seals behind the flange? And the triple seals?
     
  12. Ferrarium

    Ferrarium F1 Veteran
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    That looks like engine oil. That inspection plate under the main shaft goes to the GB oil you can inspect the ring nut there. Maybe that's leaking. Also there are 3 o-rings for the flange a big one and 2 little ones if I recall?
     
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  13. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Yes, all the seals behind the flange were changed
     
  14. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    That's my guess for where it's coming from, when I replaced the seal for the inspection cover it didn't really feel "right" when I tightened it back up. I removed it again and it looked fine, wasnt pinched or anythin but I just had a nagging doubt about it. All the seals behind the flanfe were done and they seemed to go back fine. I suspect that little cover plate is the problem, hopefully the camera can see in there tomorrow
     
  15. Ferrarium

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    I love the inspection cameras!
     
  16. emac

    emac Formula Junior
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    I thought the holes in the cover plate were there to let the oil leak out? :)

    Mine will leak a little after it sits a long time. After driving it a few times it stops.
     
  17. Ferrarium

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    ohh wow, there should be no leaks at all form anywhere, the idea that old Italian cars leak and it being part of the charm is not valid. Something is leaking because a seal is not correct.
     
  18. emac

    emac Formula Junior
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    It isnt a rust prevention option on some models? My pockets aren't deep enough to keep an old Fcar completely dry all the time.

    I am of course just kidding, somewhat. But I think Mike has a pretty good leak going on. What fluid is actually leaking? Oil, gear box oil, or brake fluid.
     
  19. Ferrarium

    Ferrarium F1 Veteran
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    it sure looks like gear box oil, its black, Mike smell it and confirm.
     
  20. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    I think (hope) its the inspection cover, it just gave me a sense of foreboding as I put it back on, time will tell..
    And if that is the case, the very next job is to flush the oil because it’s bloody terrible. Is that what a full main dealer service history gets you??
     
  21. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    I forgot to mention it smells like gearbox oil..
     
  22. Ferrarium

    Ferrarium F1 Veteran
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    Bet its that plate. its a super tight fit o-ring can get pinched very easily as the plate seats, sharp edges everywhere
     
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  23. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Well they say the camera never lies....
    I got the inspection camera inside the housing and its largely gone dry in there,or the areas I can see are. Certainly the bottom of the gearbox cover plate is dry. I wonder if it is coming from the triple seals or if it was just some residual oil that was on the clutch plate area from before spinning off?
    I'd liketo take the cover plate off the very back of the housing, part no 171408, but I guess this wouldn't be a good move as it holds the bearing and so perhaps should t be touched?
     
  24. Ferrarium

    Ferrarium F1 Veteran
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    The triple seals will leak hydraulic fluid not black oil. 171408 is just a cover nothing is back there but a sealed bearing and ring nut. No oil. If there s oil it is likely that inspection plate. You can see the plate and ring nut here. Maybe it was residual. Clean it out and see if it comes back.

     
  25. MikeeB355

    MikeeB355 Karting

    Dec 7, 2019
    82
    S Wales
    Full Name:
    Michel Bee
    Thanks Eric, we're watching it now
     

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