308 clutch change - is total oil drain necessary? | FerrariChat

308 clutch change - is total oil drain necessary?

Discussion in 'Technical Q&A' started by paul 308, Apr 30, 2011.

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  1. paul 308

    paul 308 Karting

    Jan 13, 2004
    110
    Guildford, Surrey UK
    Full Name:
    Paul Deslandes
    #1 paul 308, Apr 30, 2011
    I'm about to change the clutch on my UK dry sump '76 308 GTB and have read Birdman's 'bible' pages on the subject which I plan to adhere to strictly. However, my transmission oil was changed fairly recently and I don't want to drain and chuck it unless absolutely necessary.

    My question is, is it essential to drain the whole gearbox or will just draining the transfer case do? A quick look suggests that the oil level is below anything that will be exposed or opened up once the thing's in bits and the bellhousing removed. I'm probably wrong on this and I will have to drain it but it would mean that I only have to refill the transfer case rather than the whole transmission.

    I guess I could recover the oil, strain it and put it back in but this always goes against the grain with me and I always prefer to replace things that have any chance of causing a problem later on.
     
  2. flyngti

    flyngti Formula 3

    Jul 16, 2009
    1,218
    Snohomish, WA
    Full Name:
    Eric L
    #2 flyngti, Apr 30, 2011
    I think that its possible to do this job without draining the entire thing, but you do need to get the oil level below the lowest passage hole. I don't think that's possible by just using just the transfer case cover drain. This is a good time to change the gearbox oil anyway, right?
     
  3. Iain

    Iain F1 Rookie

    Jan 21, 2005
    3,257
    UK
    #3 Iain, Apr 30, 2011
    Most of the gearbox oil is at a lower level than the drop gear case so yes I would think its possible. Just undo the drop gear drain plug & some oil will come out of that. When its finished then you can remove the drop gear case & the bellhousing & get on with it. When you seperate the bellhousing I would have an oil catch can under it because you may well get some more out.

    WHen you are done then open up the gearbox fill plug & refill via the drop gear fill plug (slowly) till oil out starts coming out the gearbox filler.
     
  4. paul 308

    paul 308 Karting

    Jan 13, 2004
    110
    Guildford, Surrey UK
    Full Name:
    Paul Deslandes
    #4 paul 308, Apr 30, 2011
    Thanks. The oil is pretty new Redline 75W90NS so there's no need to replace it just for the sake of it. Its not like an engine where you've got combustion product contamination and would be changing as a matter of course. And Redline is not cheap so hopefully I can just refill the transfer case, topping up the main box. If it looks anything other than clean I'll replace the whole lot anyway.
     
  5. It's Ross

    It's Ross Formula 3

    Jul 30, 2007
    2,028
    Barrington, Ill. USA
    Full Name:
    Ross
    #5 It's Ross, Apr 30, 2011
    Why not drain it into a clean container and re-use it?
     
  6. paul 308

    paul 308 Karting

    Jan 13, 2004
    110
    Guildford, Surrey UK
    Full Name:
    Paul Deslandes
    #6 paul 308, Apr 30, 2011
    That really is the obvious answer and is probably what I'll do and then end up putting in new oil anyway.

    Thanks for all the replies.

    Paul
     
  7. Bagherra

    Bagherra Rookie

    Mar 9, 2006
    27
    Dark Side of Moon
    #7 Bagherra, May 2, 2011
    Anybody got a link to Birdman's site?
     
  8. paul 308

    paul 308 Karting

    Jan 13, 2004
    110
    Guildford, Surrey UK
    Full Name:
    Paul Deslandes
    #8 paul 308, May 2, 2011

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