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Correct Nuts For My D18 Tc Output?

Discussion in 'Early CJ5 and CJ6 Tech' started by Buildflycrash, Jan 18, 2023.

  1. Jan 18, 2023
    Buildflycrash

    Buildflycrash More or Less in Line. 2024 Sponsor 2022 Sponsor

    Gulf Breeze FL...
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    Finishing up the rebuild of my TC. One of the old nuts was buggered up badly. I had a spare steel locking nut that I put on the rear. Seems like the front should be a 3/4” (?) Castle Nut ?

    Y’all know exactly what I should be using? Link to purchase would be appreciated.

    Thanks.
     
  2. Jan 18, 2023
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
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    Title says D18 TC Output. I assume you are talking about the nuts that hold the front and rear output yokes?

    If so, I don't recommend using lock nuts. You want to use the "Correct Nuts" as indicated in the title of this thread.

    I have seen Nylock locking nuts used for this, and in place of a proper castle nut on the drive gear. I have also seen what happens when they come loose.

    These should be "Castle Nuts" which have been torqued to spec and secured with a cotter pin. There is a reason for that design.

    Page 71 of the Parts List shows this as being "A-980 NUT, hex, 3/4"-20 Slotted" ("Slotted means a Castle Nut).

    If you plan on doing much work with these old Jeeps getting a good service manual and parts list manual is a good investment.
     
  3. Jan 18, 2023
    Buildflycrash

    Buildflycrash More or Less in Line. 2024 Sponsor 2022 Sponsor

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    Correct. I'm searching Quadratec and 4wd but not finding it.

    edit- found them! Thanks for the help.
     
  4. Jan 18, 2023
    duffer

    duffer Rodent Power

    Bozeman, MT
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    I don't think the later D18 output shafts, front or rear, are drilled for the castle nut/cotter pin. That is the best arrangement overall from a security standpoint and because that nut has a larger base that doesn't cause the deflection in the underlying washer like the more modern factory lock nuts. The factory lock nuts are NOT nylock style but rather a flex top style lock nut. They have no plastic in them.

    I'm a little suspect of the current replacement options but Walck's lists the nut and Peter DeBella has NOS Brown & Lipe output shafts that are drilled for the cotter pins.
    https://walcks4wd.com/Nut-Transfer-Case-And-Pinion-Yolks-34-16-Thread-All-Model-Axles_p_1061.html
     
  5. Jan 18, 2023
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    Be aware the threads changed on the front outputs at some point.
     
  6. Jan 18, 2023
    oldtime

    oldtime oldtime

    St. Charles,...
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    Transfer case output shafts and nuts changed in 1954-1/2 when they went to the 1-1/4” intermediate shaft.
    Early = 3/4” x 20 castellated nut
    Late = 3/4” x 16 Hug Lock type nuts

    That said the output shafts with nuts are interchangeable from early to late.
    If your shafts are drilled for cotter pins they are early.
     
  7. Jan 18, 2023
    Oldpappy

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

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    These guys know a lot more than I do about the later stuff. The majority of my Jeep experience has been with older flat fender Jeeps and I thought all of the D18s used Castle Nuts. I didn't get into later Jeeps until I bought a CJ5 a couple years ago, and haven't needed to work on that transfer case.

    Hang around here you can learn something just about every day.

    I did find a Nylock lock nut on the bull gear of a supposedly 1950 gear box recently and since the shaft was drilled for a cotter pin I replaced that with a Castle nut and pin.

    On another gear box I was recently working on the transmission output shaft was not drilled for a cotter pin, and it had one of the Nylock nuts with a blue plastic insert. I don't trust that and have been debating with myself about whether to pull it apart and drill the shaft for a pin. Now I am wondering whether a similar "Hug Lock Nut" is available. My Parts List is for CJ2A-CJ3A so prior to 1954-1/2
     
    Last edited: Jan 18, 2023
    Rick Whitson likes this.
  8. Jan 18, 2023
    duffer

    duffer Rodent Power

    Bozeman, MT
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  9. Jan 18, 2023
    oldtime

    oldtime oldtime

    St. Charles,...
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    This shows the type of nut used by Dana Spicer after 1954-1/2. It was also used on all DS axle pinions prior to the “Stover” nuts that are currently in use.
    Most often called Hug lock or Flex lock.
    [​IMG]
    I much prefer the old “hug locks” as they can be re-used and thread locker can be added if desired.

    Stover distorted thread design…
    https://www.albanycountyfasteners.c...ver-Lock-Nuts-Zinc-Solo-1(RESIZE)_300x300.jpg
     
    Last edited: Jan 18, 2023
  10. Jan 18, 2023
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    The hug lock type nuts are also called Marsden locking nuts. The problem with the nylon locking nuts is not the design but the poor quality materials the ones from most vendors are made from. If you can find quality ones they work fine. Any concerns and a drop of threadlocker eliminates any potential issues. I use threadlocker on the hug lock nuts as well. Like Ken stated there are the early style with castellated nuts and the later style with the hug lock nuts. Also as he said you can mix and match them. Each style also uses a different size socket for the nut.
     
  11. Jan 18, 2023
    Cj5dale

    Cj5dale Member 2023 Sponsor 2022 Sponsor

    Knoxville, Tn
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    For reference, here’s a pic of the lock nut that was on my D18 output shaft.

    upload_2023-1-18_21-56-58.jpeg
     
    Last edited: Jan 18, 2023
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