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Which Is The Correct Or Better Rear Seal For The Dana 18 Transfer Case?

Discussion in 'Early CJ5 and CJ6 Tech' started by maurywhurt, Nov 14, 2019.

  1. Nov 14, 2019
    maurywhurt

    maurywhurt Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Western North...
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    These are both from Crown's online catalog - one's a closed seal, and the other is an open seal:


    Output Seal

    [​IMG]

    Replaces Part #: J0923896
    Price: (Log in to see price)
    • This is a closed seal. For an open seal, use J8123077.


    Output Seal

    [​IMG]

    Replaces Part #: J8123077
    Price: (Log in to see price)
    • This is an open seal. For a closed seal, use J0923896.
    Also, is there a National / Federal Mogul rear seal available for the D-18?
     
    Last edited: Nov 14, 2019
  2. Nov 14, 2019
    CJ Joe

    CJ Joe Truckhaven Tough!

    Pinon Hills, CA
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    My notes indicate the Timken National 473229 applies to both input & output. This is a double lipped seal. Spec'd for 1.5625" shaft.
    I can't find any dimensional specs for the Crown seal (other than the dimensions of the box it comes in! LOL).
     
  3. Nov 14, 2019
    48cj2a

    48cj2a http://bantamt3c.com

    Central Illinois
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    Mark T., Tom_Hartz and Mcruff like this.
  4. Nov 14, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    I stuck two of the double lipped F-M seals in there, not dripping.

    [​IMG]
     
    Last edited: Nov 14, 2019
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  5. Nov 14, 2019
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

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  6. Nov 14, 2019
    maurywhurt

    maurywhurt Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Thanks very much for all the help, guys. It sounds like either type of seal (open or closed) will work. I agree that a major brand name like Federal Mogul / National would be preferable to Crown, and will buy accordingly.

    I've read on other threads that installing two seals back to back has worked well for some. I think this is also what Howard referred to above. Any other thoughts on that idea?
     
    Last edited: Nov 14, 2019
  7. Nov 14, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    Just make sure you lubricate them. Otherwise the outside one will be running dry until the inside one leaks, and by that time the outside one will have been destroyed from friction.
     
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  8. Nov 14, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    FWIW I packed bearing grease between mine.
     
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  9. Nov 14, 2019
    48cj2a

    48cj2a http://bantamt3c.com

    Central Illinois
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    I've also read where guys put a good quality black sealant on the splines to prevent weeping there as well, but make sure its clean and oil free.
     
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  10. Nov 14, 2019
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    A good trick to lube seals this way is to put a piece of wool wicking material (buy from McMaster Carr) cut to fit inside the hollow body. Before you put it in, soak it in motor oil. It is then lubed for life. The wicking material is what the factory used to put inside your pilot bushing hole to oil the pilot bearing.
     
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  11. Nov 14, 2019
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

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    Great info.
     
  12. Nov 14, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    I did it like Howard said...used the FM seal that I think was just a smidge thinnier and it makes it easy to double up the install...I used a bit of grease inside the cavity for lube, but I like McRuff's idea a lot....
     
  13. Nov 15, 2019
    maurywhurt

    maurywhurt Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    That sounds like a great idea, Mike - thanks!

    Is this the wool wicking you use (the cord shape), or something different?: McMaster-Carr
     
    Last edited: Nov 15, 2019
  14. Nov 15, 2019
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    I have not used much of the cord, I have several of the sheets I keep around and I cut them from sheets. My old 70 year old lathe uses this stuff from the factory.
     
  15. Nov 17, 2019
    givemethewillys

    givemethewillys Been here since sparky ran it. 2022 Sponsor

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    So if I'm understanding this thread correctly, are people recommending NOT using the seal that comes in the "gasket and seal" kits out there (from omix, crown, and others)? My dana 18 is ready to go back together, and i need to figure out if i need to order 2 more seals!
     
  16. Nov 18, 2019
    maurywhurt

    maurywhurt Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Here are both of the National seals referenced above:

    [​IMG]

    The closed 450185 is about 0.5" thick, and the open 473229 is about 0.31" thick.

    I think I'm going to use two of the open 473229's, as using the thinner model seems to be the best option for doubling up the output shaft seals.

    I plan to get some of the wool wicking Mcruff suggested from McMaster Carr (probably the 1/4" cord), and as he suggested, soak it in engine oil and stuff it in the openings prior to installation.

    Any more thoughts or wisdom on this idea are certainly welcome!
     
    Last edited: Nov 18, 2019
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  17. Jan 28, 2023
    KarlWithaK

    KarlWithaK New Member

    Austin, TX
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    I was out wheelin’ this weekend and it looks like I had a fair amount of oil come out the front output shaft at one point. I don’t put that many miles on the Jeep and honestly it sees more miles on the occasional drive into work in 2wd vs offroad in 4wd. It has the typical slow drips but this was a bit more.

    Two questions:

    1) I noticed the oil had come out after driving in 4 low with the T18 up into fourth gear driving between trails. I didn’t see it happen when crawling in 4 low while in 1st / 2nd. I also didn’t see it happen in 4 high. Any reason that maybe the 4 low / 4th gear would force more oil out?

    2) I’ve read pretty much every thread on output shaft seals. One thing still wasn’t clear to me though. If I go with 2 seals like the FM 473229 are you adding the second seal to replace the felt or are you putting 2 seals and the felt in place?
    Thanks!
     
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  18. Jan 29, 2023
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    I didn't find there's enough room for the felt with the two seals.
     
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  19. Jan 29, 2023
    KarlWithaK

    KarlWithaK New Member

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    Thank you!
     
  20. Jan 29, 2023
    duffer

    duffer Rodent Power

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    I use doubled SKF 15655's and you can fit the felt but you have to cut the thickness in half. Not difficult to do with a sharp utility knife.
     
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