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Trans Jumping out of gear

Discussion in 'Early CJ5 and CJ6 Tech' started by Leathernek, Mar 31, 2012.

  1. Mar 31, 2012
    Leathernek

    Leathernek Member

    Northwest Georgia
    Joined:
    Mar 19, 2012
    Messages:
    110
    When I got the '63 CJ5 all together this afternoon, I drove it around the block a couple of times, and the transmission kept jumping out of 2nd gear. What would cause this? I know it may need a clutch or it needs adjusting but I just thought it was strange that it was just coming out of gear like that.....:?

    Thanks,

    Josh
     
    Leathernek, Mar 31, 2012
    #1
  2. Mar 31, 2012
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
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    9,825
    Pretty common in an early CJ5 needing a transmission rebuild, especially if it jumps out when coasting against engine compression downhill, etc.

    Not real complicated or expensive for an F-head.
     
    PeteL, Mar 31, 2012
    #2
  3. Mar 31, 2012
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
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    8,124
    Generally it's the synchros but has also been blamed on worn bearings (including the pilot bushing) and, at least in my case, a busted poppitball spring in the shift tower.

    Anyway you shake it you're headed for a tranny rebuild.

    H.
     
    Howard Eisenhauer, Mar 31, 2012
    #3
  4. Mar 31, 2012
    mortten

    mortten I can’t put my finger on it 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Peninsula, Ohio
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    Apr 17, 2006
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    Second gear famous for going bad in T-90's
     
    mortten, Mar 31, 2012
    #4
  5. Mar 31, 2012
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    Supposedly the bronze bushing inside of second gear wears. This allows the gear to skew on the shaft when decellerating, pushing the synchromesh teeth apart and disengaging.

    New second gears are available that will fix this problem.
     
    timgr, Mar 31, 2012
    #5
  6. Mar 31, 2012
    JeepPower

    JeepPower Hopeless Gearhead

    Fort Mill, SC
    Joined:
    Oct 16, 2002
    Messages:
    289
    I had the exact problem.

    For me it turned out to be a spun front thrust washer on the countershaft. The worn bushing allowed the countershaft to move excessively.

    The spun bushing also caused significant wear on the machined surfaces on the case & countershaft. Both the trans case & countershaft had to be replaced.

    Hopefully it is something as simple as a worn syncro assembly, but it wasn't for me. I reused the old syncros & the problem didn't return.

    cell post
     
    JeepPower, Mar 31, 2012
    #6
  7. Mar 31, 2012
    garage gnome

    garage gnome ECJ5 welder

    Western MA
    Joined:
    Jun 19, 2009
    Messages:
    3,093
    Sounds like I have this same problem in my '49 also. I plan on taking the body off this winter to fix some rust issues. Maybe I'll fix it then.
     
    garage gnome, Mar 31, 2012
    #7
  8. Mar 31, 2012
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,529
    First check and make sure the retaining nut is tight holding the transfer case input gear on. If this nut comes loose it will allow the mainshaft to move back and forth causing this problem.


    Sent from my iPhone using Tapatalk
     
    nickmil, Mar 31, 2012
    #8
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