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Flywheel Pilot Bushing

Discussion in 'Early CJ5 and CJ6 Tech' started by Howard Eisenhauer, Jan 25, 2006.

  1. Jan 25, 2006
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    8,135
    O.K. folks here's today's question-


    What is the tranny/flywheel pilot size supposed to be? I've got two T90 shafts on hand that both measure .5 sumthing-or-other" diameter & my two F134 flywheels both have noticebly larger holes. What is the allowable clearance between the trannny input gear & the pilot bushing in the flywheel?

    I'm guessing that this is a bit excessive-

    [​IMG]

    Thanks,

    H.
     
    Howard Eisenhauer, Jan 25, 2006
    #1
  2. Jan 26, 2006
    lynn

    lynn Time machine / Early CJ5 HR Rep Staff Member

    Huntingdon PA
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    Sep 20, 2002
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    3,437
    I show the T90 has a tip diameter of .629, where a T86 has a tip of .590

    T98s show input size of .625 or .670

    Looks like a bad match in the pic.
     
    lynn, Jan 26, 2006
    #2
  3. Jan 26, 2006
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    4,275
    Not sure of the exact spec for the transmission input shaft to the pilot bushing, but you definitely have too much slop in that picture. I've always just replaced the bushing with a new one and checked it for a nice slip-fit.
    Nice and scientific, huh? :rofl:
     
    w3srl, Jan 26, 2006
    #3
  4. Jan 26, 2006
    $ sink

    $ sink Gazillians of posts

    Virginia Bch
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    Nov 25, 2004
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    :voice of experience: a wallowed out pilot bearing is generally a symptom of bad or going bad bearings in the transmission main shaft. check your main shaft bearings carefully, or just rebuild your tranny. I had the same issue with my t14, I replaced the bushing and left the tranny alone. now I'm getting a noise once in a while that leads me to believe that the bearing in the tranny where the input and output shafts come together is worn and allowing too much slop which will result in another bad pilot bearing :voice of experience off: :rofl:

    $.02:coffee:
     
    $ sink, Jan 26, 2006
    #4
  5. Jan 26, 2006
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Clearance on the diameter should be 3-4 thou, according to an old post by mcruf.
     
    timgr, Jan 26, 2006
    #5
  6. Jan 26, 2006
    GreenKaiser

    GreenKaiser Flamed out again....

    Nashville, TN
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    Nov 23, 2005
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    IMHO you should always dump the bushing and machine the flywheel for a bearing. Note: the T-90 input shaft doesn't match any bearing (at least none that Dixie Bearings had listed) so you will need to find one close and have the bearing ID opened up.
     
    GreenKaiser, Jan 26, 2006
    #6
  7. Jan 27, 2006
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    8,135
    Thanks everybody, turns out the shaft is actuall .623, book value is .625. The pilot bearing is suppose to be .628. I'll get the bearing replaced & the flywheel surfaced when I send the engine out for work. the tranny is already apart, as well as the xfer case & just about everything else in prep for a complete rebuild :).

    H.
     
    Howard Eisenhauer, Jan 27, 2006
    #7
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