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Transmission jumps out of second gear

Discussion in 'Flat Fender Tech' started by 97XJ_95YJ, Mar 15, 2007.

  1. Mar 15, 2007
    97XJ_95YJ

    97XJ_95YJ I hate torx bolts

    Woolrich, PA
    Joined:
    Feb 3, 2006
    Messages:
    251
    The transmission likes to jump out of second gear when I'm on hills. I'm told this is a common problem with flat fenders. Is this an easy fix or is my tranny about to go? Oh yeah, I should add that I'm talking about my stock T-90. Thanks.
     
  2. Mar 15, 2007
    $ sink

    $ sink Gazillians of posts

    Virginia Bch
    Joined:
    Nov 25, 2004
    Messages:
    1,375
    syncros and worn bearings
     
  3. Mar 15, 2007
    Andy4802

    Andy4802 Canadian Jeep junkie

    Hudson, Qc, Canada
    Joined:
    Jul 30, 2006
    Messages:
    410
    yup, mine does it too... seems to happen most when i let off the gas a bit in second gear... I'm gonna live with it for now since im planning on swapping it out anyway.
     
  4. Mar 15, 2007
    Shannon

    Shannon New Member

    Skippers, Va
    Joined:
    Jun 13, 2006
    Messages:
    27
    I have the same promblem with my 75,we are planning on doing a swap.
     
  5. Mar 15, 2007
    w3srl

    w3srl Semi-homeless in Florida Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
    Messages:
    3,959
    With the T-90 the bushing in the second gear wears, as do the synchros. Verry common issue with the T-90. I ordered up all the parts to do a full-on rebuild of the T-90 and D-18, but they're sitting on the bench waiting for me to get the time to do the job..
     
  6. Mar 16, 2007
    97XJ_95YJ

    97XJ_95YJ I hate torx bolts

    Woolrich, PA
    Joined:
    Feb 3, 2006
    Messages:
    251
    Who's got the best deal on a rebuild kit?
     
  7. Mar 16, 2007
    jd7

    jd7 Sponsor

    Nacogdoches,Texas
    Joined:
    Mar 30, 2004
    Messages:
    1,749
    e-bay has them listed for what seems to be a good price....can't answer how good a deal it would be though....
     
  8. Mar 16, 2007
    Boyink

    Boyink Super Moderator Staff Member

    Ava, MO
    Joined:
    Sep 20, 2002
    Messages:
    4,977
    Welcome to the old Jeep club...you're dealing with issues that have driven conversations around campfires for over 4 decades now...;)
     
  9. Mar 16, 2007
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    5,973
    Theres "cheap" , & theres "good". "Good" has better bearings, a new 2nd gear & a new idler shaft. Did "cheap" the last time, this time I went with the Novak kit from Herm, a bit more money, but "good" :)

    Download the T90 rebuild guide from Rick Stivers, found here-

    http://www.willystech.com/wt/T90RebuildGuide/T90rebuild.htm

    Picks of my rebuild ( & if you're inclined, backup light switch mod:) ) are here-

    http://www.tantel.ca/Images/The Sludge Pile/Section_J_Transmission/

    A note on diss-assembly, when you get it out of the vehicle, take the shift tower off, hold it upside down over the bench & shake. Diss-assembly is now complete R) .

    H.
     
  10. Mar 16, 2007
    michigan_pinstripes

    michigan_pinstripes I'm not lost, I'm wandering

    Clarkston MI...
    Joined:
    Aug 20, 2003
    Messages:
    606
    I've installed one of Herm's that was part of his 4 cyl T90 to V6 conversion. gud stuff 8)

    You dont really even need a manual, its not as difficult as it sounds. punch out counter rotation set shaft <bottom shaft> to allow gearset to rest in bottom of the case. Main set comes right out to and takes minutes to replace worn items. Have a spare T-90 handy as you may have to combine shafts and gears of both to make one good tranny. Herm's kit should have needle bearings for the lower counter set -- I used vaseline to hold them in place for the re-install of that lower pin <shaft>

    I need to build a spare T90 as a matter of fact
     
  11. Mar 18, 2007
    endless expense 45

    endless expense 45 Oldsmobile RTI Ramp!

    Stony Creek VA.
    Joined:
    Jul 26, 2005
    Messages:
    177
    Used the cheap kit on my 45 MB T-84 trans jumps out of second gear also.To agree with others spend the extra money and get the GOOD kit.
     
  12. Mar 18, 2007
    97XJ_95YJ

    97XJ_95YJ I hate torx bolts

    Woolrich, PA
    Joined:
    Feb 3, 2006
    Messages:
    251
    So what would be in a "good" rebuild kit that the others wouldn't have?
     
  13. Mar 18, 2007
    Andy4802

    Andy4802 Canadian Jeep junkie

    Hudson, Qc, Canada
    Joined:
    Jul 30, 2006
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    410
  14. Mar 22, 2007
    jalbrecht55

    jalbrecht55 Member

    State College,...
    Joined:
    Dec 16, 2006
    Messages:
    60
    I've been having the same problem, (or 'had' the same problem) with my T90. I decided to go with the full kit from Herm which should help, but honestly, there are a few things not replaced in this kit that can be the real source of your problem. I think the most common is wear on the small synchro teeth (not the right name, but hope you know what I mean) on the 2nd gear itself and wear on the sliding collar that ties 2nd gear to the mainshaft when you are in 2nd gear. Herm's recommendation is if there is any wear whatsoever on the gear or the collar, to go ahead and replace the worn parts. It is a little pricey, ~100 for the whole mess, but should fix the problem for a long time.

    The other thing I noticed on my tranny is that depending on the amount of wear on the shift fork, and where the tower is actually bolted down (note there is some slop between the tower and the case) you may or may not be fully 100% seating the collar into 2nd gear. Since the actual connection between the teeth and collar is only about 3/16", you might try shifting the shift tower back and/or replacing or building up your shift fork. If it's already jumping out of gear, the damage is done, but it might help prevent wear in the future. (If you move this stuff too far to the rear, you'll start having problems with 3rd gear and/or start wearing down the collar or fork because you're pushing against 2nd gear a little too hard , so I'd be careful with that one.)

    And then the last thing you might do (band-aid IMO) are stiffer springs for the shift detent balls.

    One last thing worth mentioning is that some of the new jeeps (rumor is CJ-3B) have a slightly lower gear ratio. You can swap the input gear and I'm blanking on the name, the lower counter rotating gear set, which will drop first from ~2.8:1 to about 3.38:1. 2nd also drops a similar percentage.

    I did all of the above and the end result is that I've got more time and $$ tied up in my T90 than any sain person should, but what the heck, I also could have had a 300hp V8 and instead I've got a freshly rebuilt L134. To each their own. Or something like that :)
     

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