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Which tranny?

Discussion in 'Flat Fender Tech' started by Yankeefist, Nov 15, 2009.

  1. oldtime

    oldtime oldtime

    The complete CJ version of the T90 weighs in right near 60 lbs.
    The complete CJ version of the T98 weighs in right near 160 lbs.
    That has a significant effect on the military light reconnaissance vehicle (LRV) stipulation concerning curb weight.

    Seems I'm starting to digressing off topic.
    Yet I feel it is credible input because the original military stipulations created the Jeep itself.
    All of our CJ's are just an afterthought.

    Neither could the prototype nor the production LRV's make the grade concerning acceptable curb weight.
    The military upped the allowable curb weight becuse all contenders for the government contract were over scale.
    If I recall correctly they upped the acceptable curb weight twice.
    I think the original stipulation was 1800 then 2000 then 2200 lbs.
    I have those numbers somewhere at home but anyway the military guys should know the exact numbers for sure.

    Keep it light and get it right !
     
  2. Daryl

    Daryl Sponsor

    X2 on the t-90 being the best set-up if behind the 134. I swapped in a t-98 in my 71 and Love it behind the 225.
     
  3. willysworker

    willysworker Member

     
    Last edited: Dec 19, 2009
  4. Mcruff

    Mcruff Earlycj5 Machinist

    A little correction to the info about the t98 versus the t90. 1st gear on the
    t98 is 6.4:1 not 7.8:1, the t90 weighs 75 lbs and the t98 weighs in at 145lbs, adapters would be extra weight. The t98 is 3.5" taller than the t90 but when the t98 is installled the engine and transmision are effectively raised a little
    in the frame to aid in ground clearance, thats why there were special tranmission cover for the floor pan.
     
  5. jpflat2a

    jpflat2a what's that noise?

    I believe he was talking about reverse gear being this ratio, not first.
     
  6. Mcruff

    Mcruff Earlycj5 Machinist

    My bad, reverse is a little better than 7.8 but not by much.
     
  7. oldtime

    oldtime oldtime

    I repeat....
    Don't forget T98-A will give you a crazy slow reverse gear as in 7.8 to 1 ratio.

    I maintain that the complete caneshift T90 for CJ application is about 60 lbs without gear lube. (From actual scale reading)

    I maintain that the T98-A with its original cast iron adapters is about 160 lbs without gear lube. (From actual scale reading)

    The T98-A rear engine support crossmember is lowered from the frame rail flange by exactly 1" via spacer blocks.
     
  8. Mcruff

    Mcruff Earlycj5 Machinist

    Yes the crossmember is lowered but the transmission is 3 1/2" taller so effectively the trans is raised.
     
  9. Daryl

    Daryl Sponsor

    Just raise the body up on poly spacers 1" and lower the crossmember 2" and floor is very easy to piece together. The t-98/t-18 works great behind the Buick motor.
     
  10. DoubleBit

    DoubleBit Member

    IMHO: 5.38s are the best thing that ever happened to my MB. I'm running a crusty old F-head, t-90, d18, and husky OD, and some funky aggressive farmer 7.00x15 M+Ss..
    With the original 4:88s (?) it would barely pull third on any kind of a grade or head wind.
    With the 5.38s and that OD, I can on flat ground pull a fairly steady 50-55 mph.. I'd love to upgrade to the V6 but would never ever raise my final drive gearing.