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Swapping T14 Out For A T15 - Drive Shaft Question

Discussion in 'Intermediate CJ-5/6/7/8' started by Mark Landry, Nov 20, 2019.

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  1. Nov 20, 2019
    Mark Landry

    Mark Landry New Member

    Denver
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    i have a 74 cj 5 with an amc 304 and, somehow, a t14 transmission that I’m hearing is too weak for the 304.

    My understanding is that a t15 should bolt up without any hassle/adapter/etc, but I’m wondering if I’ll need a shorter rear drive shaft and a longer front one as the t15 is about 1.5 inches longer than the 14?

    Is 1.5 inches a huge deal?
     
  2. Nov 20, 2019
    73 cj5

    73 cj5 Not ready for the junkyard yet 2020 Sponsor

    Mississippi
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    I have my doubts. There’s a joke in there...
    This might be better suited for the intermediate section.
     
  3. Nov 20, 2019
    sterlclan

    sterlclan Member

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    Ran a t14 behind a 304 for a few years it is currently in my boys 70 behind his v6 I replaced it with an np435 so cant answer thedriveshaft question. The t14 will last if you are aware of how much throttle you use
     
  4. Nov 20, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

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    Thread moved to intermediate tech...
     
  5. Nov 20, 2019
    zila

    zila I throw poop

    Rock Springs,...
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    Redoing a drive shaft is no big deal. I have had mine modified twice at Six States.. They just need the correct measurement..
     
  6. Nov 20, 2019
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    Yes, the T-15 will bolt in. Parts book says the CJ-5 uses the same driveshafts for all 3-speeds in 1974.
     
  7. Dec 19, 2019
    Mark Landry

    Mark Landry New Member

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    Awesome. Thank you
     
  8. Dec 19, 2019
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

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    Hi Mark - thinking about this some more, the 232/258 is longer than the 304, and correction for the transmission length may be built-in to the engine placement. The 304 never came with the T-14, and the 232/258 never came with the T-15. It should be close, since the location of the transfer case, cross-member and transmission shifter stalk does not change. Possibly you could move the engine forward slightly, depending on the distance from the radiator to the fan, and keep everything else in the same place. If you do, make sure you have plenty of clearance from the engine to the axle - I think it will be ok, but you'll have to be there to be sure.
     
  9. Dec 19, 2019
    oldtime

    oldtime oldtime

    St. Charles,...
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    Just a few thuings that I recall about T14 vs T15...

    T14 only available with 10 spline maindrive.
    T15 only available with 6 spline maindrive.
    So maindrive (TC input gears will be different.
    Other wise both bolt direct to TC

    T14 case is 8-3/8" OAL.
    T15 case is 10" OAL

    So I'm thinking any difference in total drive train length will be in the factory bellhousing and adapters.
     
  10. Dec 19, 2019
    sterlclan

    sterlclan Member

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    Fwiw I put a 304 where a 232 lived direct bolt in,mounts lined up. I would guess the driveshafts would have been the same the bell for the t14 is long and the one for the t15 off the 304 was short thus making up the difference in trans length.
     
  11. Dec 19, 2019
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

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    T-14 and T-15 use the same bell housing, regardless of engine. No engine adapter for any 1974 3-speed application except the T-15 in a V8 Wagoneer or J-truck, which has a much longer input shaft anyway.

    To the OP, what's the VIN for your Jeep? If it came with a six, and the 304 was swapped in, you are likely going back to the proper alignment, with a 304 and T-15.
     
  12. Dec 19, 2019
    oldtime

    oldtime oldtime

    St. Charles,...
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    That's exactly what I was thinking.
    Very Interesting !
    So as long as the transfer case does not move fore nor aft; then that implies the engine mount location must change as you had previously stated.
     
  13. Dec 19, 2019
    sterlclan

    sterlclan Member

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    its the same i bolted the 304 to the original frame mounts where the 232 lived never moved transmission was almost certian the bell off the 304 was a different depth actually the whole swap was plug and play used the same radaitor for a while till it leaked wiring harness plugged right in
     
  14. Dec 19, 2019
    oldtime

    oldtime oldtime

    St. Charles,...
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    Oh now I understand.
    There are diiferrent engine lengths envolved here.
    I was thinking the engine mount location must change if the engine length remains the same.

    Fascinating Intermediate Tech !
     
  15. Dec 19, 2019
    sterlclan

    sterlclan Member

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    It’s all a learning experience when working on an intermediate. The only thing I did was add a hole for the isolaters in the frame mount as the v8 had an additional bolt to the frame mount
     

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