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T86 To T14 Swap

Discussion in 'Early CJ5 and CJ6 Tech' started by jeepstar, Nov 6, 2022.

  1. Nov 6, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    The "double gear" next in line does not rotate fully. I cannot count the gear teeth
     
  2. Nov 6, 2022
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I know you don't want to hear this
    the T 14 - 10 spline is a unicorn
    29 tooth output gear can be found in 6 or 10 spline
    not so much as finding a 26 tooth - 10 spline
     
    dnb71R2 likes this.
  3. Nov 6, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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  4. Nov 6, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I want to hear everything about this so I can correct it.
     
  5. Nov 6, 2022
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    39 - 18 intermediate gear on novak chart . would indicate a 29 tooth output gear
    could be my eye balls but the mesh looks off
    [​IMG]

    now that you have it apart . hand fit the 10 spline gear into intermediate gear
     
    FinoCJ likes this.
  6. Nov 6, 2022
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    So that would be a large hole D18 - that was the standard case on v6 jeeps. Whether mounted behind the T86 or T14, it originally would have had an intermediate gear (double gear) with 39 and 18 teeth.
    As Ron is pointing out, your intermediate gear count of 40-18 might have a slight miscount on the big end - is it really a 39 and 18 tooth counts on the two ends? That would be appropriate for the original, large (4") hole, v6 application.
    Was the T86 mated to the D18 and running/driving? If that intermediate gear is truly a 39-18 tooth, then that 26tooth drive gear on the T86 is NOT appropriate. How does the 26 tooth drive gear mesh/fit with the intermediate gear when the T86 is mated to the D18? Is it a bit sloppy? If so, it is quite possible that the 29t T14 gear you have is the appropriate gear - it IS the correct gear for an intermediate gear with 39-18 tooth count.
     
    Fireball likes this.
  7. Nov 7, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    They were bolted together, but not installed in the jeep. Now that the jeep is mine the owner is suspiciously not responding to my calls.

    I will recount the gears after work today. If it is a 39 tooth count I can just bolt it up to my transmission to move on with my project?

    There appears to be a broken chunk out of the front output Circle is that normal?
     
    FinoCJ likes this.
  8. Nov 7, 2022
    homersdog

    homersdog Tulsa, Ok 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Here is a picture of mine from a couple of years ago. You can sort of see the front mounting hole. I think yours looks the same.

    [​IMG]
     
    Last edited: Nov 7, 2022
    jeepstar likes this.
  9. Nov 7, 2022
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    transmission oil return holes
    DSCN0330 - Copy (2).JPG

    let us know . what you find . I think the 29 tooth is the gear
    carry on
     
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  10. Nov 7, 2022
    Keys5a

    Keys5a Sponsor

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    We’re all interested in the intermediate gear, not the output gears with the sliding gear that you have a couple photos of. Measure the intermediate shaft diameter (the shaft with the 39/18 gear). A large hole case (4”) should measure 1-1/4”. The older small hole cases used 1-1/8”. There should be a stub sticking out a little past the case with a lock plate holding it.
    It looks like you might have the right transfer case, only some one mistakenly put a 26 tooth drive gear where a 29 tooth should have been. And I thought I had seen it all!
    -Donny
     
    Last edited: Nov 7, 2022
  11. Nov 7, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Isnt that the photo with 40/18 written on it?
    I will recount the teeth, and measure that shaft after work today, first thing.
     
    FinoCJ likes this.
  12. Nov 7, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Should i use copper spray gasket between the tranny/tcase when i put them together?
     
  13. Nov 7, 2022
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

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  14. Nov 7, 2022
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

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    Yup....I'd test fit it dry first (no gasket) just to make sure the 29t gear fits. Also, check the diameter of the intermediate shaft to confirm 1.25"

    Yes

    Typically the copper spray is used on the shims under the rear bearing cap. For the main gasket, a lot of us use a thin smear of permatex or rtv, or a thin gasket sealer like high tack, or you can even go dry - but helps to have something hold it in place while wrestling the two pieces together.

    As 47v6 mentioned, it's probably worth considering a rebuild now that it's on a bench?
     
    Last edited: Nov 7, 2022
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  15. Nov 7, 2022
    colojeepguy

    colojeepguy Colorado Springs

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    At the very least I would replace the intermediate shaft and bearings.
     
  16. Nov 7, 2022
    duffer

    duffer Rodent Power

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    The 4" index case was never offered in anything but the 1.25" intermediate shaft, D20 or D18. I'm another that would have that completely torn down NOW while it is already partly apart. The main drive gear/intermediate gear mesh appears to be a BIG red flag. With the driveshafts off, all that should turn freely with the transmission in neutral. If it doesn't there is a real problem. You obviously can not run a 26 tooth gear set with the 10 spline main drive gear and you really don't want those anyway. The spur gear tooth profile on that earlier 2.43:1 set is significantly less robust than the 2.46:1 gear set.
     
  17. Nov 7, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    It's 39, not 40.
     
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  18. Nov 7, 2022
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

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    I'd test fit the T14 to the D18 using the 10spline/26t gear....I think its going to work. But check the teeth on the small intermediate gear and mesh - if it was run with the 26t gear, there may be damage.
     
  19. Nov 7, 2022
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    It does look like you should be all set. It seems like they had the wrong gear on the back of the transmission when they were doing whatever work they were doing with it.
     
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  20. Nov 7, 2022
    Keys5a

    Keys5a Sponsor

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    I would at least pull the intermediate gear and check the condition of the shaft and rollers. If you have an original shaft, they were properly surface hardened and often these show no wear other than burnishing. Many aftermarket shafts wear terribly with very few miles.
    I have many times re-used an intermediate shaft on overhauls.
    -Donny
     
    colojeepguy, OzFin and 47v6 like this.
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