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T90 question

Discussion in 'Early CJ5 and CJ6 Tech' started by ilovemyjeep, Sep 17, 2005.

  1. Sep 17, 2005
    ilovemyjeep

    ilovemyjeep 1971 CJ-5 w/ Dauntless V6

    Atlanta, Georgia
    Joined:
    Jul 20, 2005
    Messages:
    74
    Well back to my original problem of the horrible noise from my t-case / trans. turns out i goofed up the mainshaft quite a bit because i dropped some roller bearings but anyhow, it's going to be cheaper to buy the long mainshaft for a t90 / d18 setup (because i have a spare t90/d18 lying around). Will swapping my t14 for the t90 affect my acceleration / top speed, etc?
     
    ilovemyjeep, Sep 17, 2005
    #1
  2. Sep 17, 2005
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
    Joined:
    Sep 20, 2002
    Messages:
    6,197
    1st 2nd 3rd 4th 5th Rev
    T-14 3.10 2.61 1.00 3.10

    T-90 2.98 1.66 1.00 N/A


    Looks like biggest difference will be a taller 2nd.
     
    Boyink, Sep 17, 2005
    #2
  3. Sep 17, 2005
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
    Joined:
    Jul 30, 2003
    Messages:
    8,525
    hmm Mike, I came up with diff ratios than you:

    T90- 3.33, 1.55, 1.00, and 3.79 for reverse

    T-14- 3.10, 1.61, 1.00, and 3.10 for reverse

    the only real benefit switching to T14 would be the synchro 1st gear
    also, if you have Warn OD with the T90, it won't work with the T14
    diff spline count
     
    jpflat2a, Sep 17, 2005
    #3
  4. Sep 17, 2005
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
    Joined:
    Sep 20, 2002
    Messages:
    6,197
    I'd believe your numbers Jim...I grabbed those from JeepTech.com.
     
    Boyink, Sep 17, 2005
    #4
  5. Sep 17, 2005
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
    Joined:
    Jul 30, 2003
    Messages:
    8,525
    there also was an early T90 wagon/pickup trans that had lower first gear/cluster ratio, but they are a little hard to find. The end result is a lower first gear ratio only IIRC.

    lovemyjeep: T90 parts are plentiful, maybe repair what you have.
     
    jpflat2a, Sep 17, 2005
    #5
  6. Sep 17, 2005
    kamel

    kamel Senior Curmudgeon

    Erlanger, Kentucky
    Joined:
    Jun 10, 2003
    Messages:
    891
    t-90 first gear numbers were right (in both posts)

    Somewhere along the line the first gear ratio changed slightly. If the transmission has not been fooled around with the 3.3 ratio will be indicated by a threaded shift rod (for the knob). The older 2.98 ratio did not have a threaded rod......
     
    kamel, Sep 17, 2005
    #6
  7. Sep 17, 2005
    fourtrail

    fourtrail Built not Bought

    Carlinville,...
    Joined:
    Jan 24, 2004
    Messages:
    204
    You can also get a t-90 from an early scout that is the lower first. Just have to change to the jeep input shaft. Also should have an 18 without the rear brake assembly.
     
    fourtrail, Sep 17, 2005
    #7
  8. Sep 17, 2005
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    5,349
    This is off of Novaks sight:
    The T90A has:
    1st 2.98
    2nd 1.66
    3rd 1.00

    The T90C has:
    1st 3.44
    2nd 1.85
    3rd 1.00
     
    Mcruff, Sep 17, 2005
    #8
  9. Sep 17, 2005
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
    Joined:
    Jul 30, 2003
    Messages:
    8,525
    thanks Kamel and Mike !
    knew that info was floating around out there somewhere
     
    jpflat2a, Sep 17, 2005
    #9
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