Transfer gear / transmission oil | FerrariChat

Transfer gear / transmission oil

Discussion in 'Boxers/TR/M' started by JohnMH, Apr 25, 2019.

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  1. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,625
    Dubai / Bologna
    Perhaps a simple question, is the oil in the stacked set of transfer gears which deliver power from the engine to the transmission shared / circulated with the oil in the transmission?

    If so, it always seemed odd to me to set the oil level at the bottom of the fill plug, then add more.

    If not, how much oil does the transfer case need? The manual seemed off by expressing the figure in weight, not volume.

    My recurring shift shaft seal leak has me thinking I may have overfilled.
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, Apr 25, 2019
    Last edited: Apr 25, 2019
    Yes (but the transfer gear reservoir is located above the main reservoir -- like a "waterfall" situation)

    The TR OM has a misprint of "17 pints" for the transfer gear reservoir capacity -- it should be "0.17 pints" (which is the 100 grams shown in the TR WSM). The best way is to first put maybe 1/2 quart into the transfer gear reservoir fill hole (the excess over the 0.17 pints will eventually overflow into the main reservoir while you do the next step). Then fill the main reservoir up to the main reservoir fill plug hole. Alternatively you can put the entire ~10 quarts in thru the transfer gear fill hole until it runs out the main reservoir fill hole, but the drain rate between the two reservoirs is quite slow.

    If you think you have over-filled it, just remove the main reservoir fill plug and let the excess run out until it stops - then put the main reservoir fill plug back in.
     
  3. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,625
    Dubai / Bologna
    Thanks, I learned something new.

    From the perspective of someone who has not been under as many TRs, what fraction of them leak significant gearbox oil from the shift shaft seal?
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Leaking a "significant" amount of gear oil from the TR shift shaft seal certainly hasn't been a common complaint here. It might be fair to say that many weep some, or drop a few drops from there. Are you sure that it's actually coming out between the seal ID and the shaft OD? Something like a crack or some porosity in the casting (under the boot or at the seal OD) would appear the same -- just a thought...
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
    Austin TX
    Full Name:
    Brian Crall
    Not terribly uncommon but also not something that needs to be lived with. Not a great seal design but typically not until the O ring gets a little hardened from age do they leak.

    Steves description of the relationship between the oil in the transfer gear reservoir and the transmission itself was excellent but I'll add something. The gear box is a small swimming pool full of oil. There are 2 significant sized holes communicating between the two at the rear of the overall unit. When a transmission is operating it looks like a blender inside. Additionally under acceleration there is a considerable wave of oil headed to the back. Between those two situations there is considerable exchange of oil between the two compartments.
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Just to back up a little, does "recurring" mean:
    1. You've never replaced the shift shaft seal, and the leaking has just gotten worse and worse until it is now significant, or
    2. You've replaced the shift shaft seal, and the new one is still leaking significantly?

    For #1, I'd call that normal (and it should've been replaced when the leaking got past a few drops). For #2, I'd call that unusually abnormal.
     
  7. Mr.Chairman

    Mr.Chairman F1 Rookie

    Mar 21, 2008
    2,987
    New Jersey
    Full Name:
    Robbie
    Not a big deal to change the seal next engine out. A little weeping here and there but you should not be leaking any significant amount.

    R
     
  8. JohnMH

    JohnMH Formula 3

    Jan 28, 2004
    1,625
    Dubai / Bologna
    I am on my second replacement seal in 10 years of ownership; the seal always dripped a little, but got worse in the last year.

    The rubber bellows which protects the seal area has oil in it while the surrounding area is dry, so the seal is the likely culprit. Do I pull the bellows over the ridge on the shift shaft? I assume so.

    The current rate of leakage is if I park the car for a week, the oil stain under it will be bigger than my hand. I intend to check the level this weekend.
     
  9. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,097
    Canada
    Full Name:
    Newman
    Yes you pull it over the flange.

    Make sure the shaft isn’t pitted of course, I’ve seen that and replaced the shaft. I’ve also seen a lip seal used in the 512 TR and in the 83 boxer I just finished it had the o-ring but also a lip seal in the recess under that bellows. The seal was perfectly fine so I put in a new o-ring and left the seal in place.
     

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