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T86aa Transmission Question

Discussion in 'Early CJ5 and CJ6 Tech' started by Cold Warrior, Dec 17, 2021.

  1. Dec 17, 2021
    Cold Warrior

    Cold Warrior New Member

    Quincy CA.
    Joined:
    May 6, 2021
    Messages:
    15
    Calling all CJ5 experts...

    Directly under my T86 main input shaft there is this hole between the transmission case and the adapter casting that bolts to the clutch housing. It sits below the fill line and it leaks, so "There's a hole in the bottom of the sea." So yeah, it leaks. See accompanying photo.

    There are threads inside, and since it's below the fill level, it seems that a "threaded something" must go inside to prevent it from continuously leaking. I don't see the part listed on the exploded diagram in the service manual.

    I have the transmission out and I am going through the seals and gaskets because the T86 and the Dana 18 T-case are both leaking...badly.

    Who knows (by that I mean, does anybody know) what that hole is, what it's for and what, if anything, threads inside to prevent the black sea from leaking.

    Thanks in advance! transmission_hole.jpg
     
  2. Dec 17, 2021
    Andrew Theros

    Andrew Theros Member 2022 Sponsor

    Los Osos, CA
    Joined:
    Feb 24, 2021
    Messages:
    168
    I am going to guess that it is your countershaft.
    If you aren’t going to open it up and rebuild the whole thing, just clean the area well and smear some RTV around it before mating it to your adapter.
     
  3. Dec 17, 2021
    Cold Warrior

    Cold Warrior New Member

    Quincy CA.
    Joined:
    May 6, 2021
    Messages:
    15
    Okay, that's a plan. It's weird that it was leaking right? That shaft doesn't rotate.

    Maybe I am wrong...maybe the leak is coming from the housing above it? The oil was all over. I am changing the gasket and seal for the input shaft, so I will do all of those things.

    Thanks! This is the first time I have worked on a CJ5 or this transmission and T-case. That explains my rookie-isms.
     
  4. Dec 18, 2021
    Andrew Theros

    Andrew Theros Member 2022 Sponsor

    Los Osos, CA
    Joined:
    Feb 24, 2021
    Messages:
    168
    If you are a rookie, then I’m a freshman.
    I rebuilt my T-14 earlier this year and had similar questions.

    You are correct, the shaft does not rotate. Hose it out with brakeclean, and seal it when you re assemble.
    The bearing retainer may be leaking, but a careful gasket replacement will cure that
     
  5. Dec 18, 2021
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,022
    That is the transmission countershaft. Not threaded regardless of appearance. The counter gear/countershaft bore in the case gets “oblonged” or egg shaped vertically.
    A little sealer may temporarily alleviate the leak but not for the long term. If there is vertical play in the shaft/case then case needs replaced.
     
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