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D18 That Doesn't Leak..... Is It Possible?

Discussion in 'Early CJ5 and CJ6 Tech' started by jwmckenzie, Apr 2, 2017.

  1. Apr 2, 2017
    jwmckenzie

    jwmckenzie Sponsor Sponsor

    Boston, MA
    Joined:
    Mar 16, 2012
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    I am rebuilding my Dana 18, mostly because I am tired of pans and cardboard under the jeep. Last season I leaked out about a pint of Gear Oil.

    When I installed the Overdrive and PTO, I was advised not to use any sealant on the gaskets, not the major source of leaks, but the gaskets were all oil soaked when I took it apart. Won't assemble dry again.

    I put a new seal in the front and rear output shafts last year. When I took it apart, the felts were all oil soaked and I know they were leaking from these seals. As well used RTV on the splines, as advised here in several posts.

    I have ordered new Front yoke and Rear companion flange, both were worn where the seals ran, so maybe that will fix the leaking from the front and rear shafts.

    I have long used Permatex #2 for oil applications, and Permatex Ultra Black RTV for anything water related. Old mechanics who worked in my Dad's shop used Indian Head Shellac.

    So here is the questions;

    1. What Sealer to use on the gaskets? The things I have read or viewed suggest copper spray for the shims, RTV for the pan gasket, and Permatex aviation gasket for most mating surfaces and Permatex thread sealer for the bolts.

    2. Advise on Output Seals, use two or just one? I think there is room for two seals if you leave out the felt.

    I am convinced it is possible, just need to know the knacks.

    Please help..........
     
  2. Apr 2, 2017
    mike starck

    mike starck Member Sponsor 2019 Sponsor

    salem,oregon
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    Well this should be interesting. Neither of my D-18 are leaking at this time so I know it is possible.The key is for how long.
    The leak I have had problems with is the speedo cable at the transfer case.I have found a fix so time will tell on that too.
     
  3. Apr 2, 2017
    Twin2

    Twin2 wasn't me Sponsor 2019 Sponsor

    Virginia Beach, VA
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    all paper gaskets . brush on sealer only . I also use it on the bolts too . RTV only on the shaft splines
    and make sure vent isn't clogged up with mud or old grease
    make sure all surfaces are oil free
    there's always been talk about using two seals . I never have
     
  4. Apr 2, 2017
    Tomellen

    Tomellen Member

    Ticonderoga, NY
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    I'm working on mine now, so I will be interested in this thread. I have worked on cars etc for years and I'm no RTV expert, but red high temp RTV has always been my go to sealant for gaskets or threads. One of the things you have to be careful on these forums is the variety of replies u get. Some are expert advisors with a lot of experience (which I am not) and some are not so experienced. This forum seems pretty balanced and people are not afraid of challenging replies. What I do is listen to everyone, read all I can then make a decision based on what I have learned, my experience and what I think will work. For instance I just installed a PTO on a Dana 18. The first installation I used rtv only on the PTO side of the gasket because if I ever removed it the gasket would stay with the PTO and I could reuse. After thinking about it and wanting no leaks, I removed the PTO and used RTV on both sides of the gasket. That made the most sense to me.
     
  5. Apr 2, 2017
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

    Medford Mass USA
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    You guys have read all the old posts about this topic, haven't you? site:earlycj5.com leaking transfer case - Bing - this is not a new topic.

    There are several locations that need special treatment - sealant on the splines, the seals, worn yokes, sealant between the shims, a straight pan, bolt threads, probably some I don't recall.
     
    Last edited: Apr 2, 2017
  6. Apr 2, 2017
    Daryl

    Daryl Sponsor Sponsor

    Bonney Lake, WA
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    And if it isn't leaking, it is probably already out of oil.:D
     
    william_cj3b, jeepermc, Twin2 and 3 others like this.
  7. Apr 2, 2017
    Steve's 70-5

    Steve's 70-5 Member

    Louisville, Ky
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    I use Permatex "Right Stuff" They call it a gasket maker. Not a big fan of silicone products
     
  8. Apr 2, 2017
    Tomellen

    Tomellen Member

    Ticonderoga, NY
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    Yea,

    I have read every one of them and taking them all into consideration. Thanks
     
  9. Apr 3, 2017
    Rick Whitson

    Rick Whitson Detroit Area Sponsor 2019 Sponsor

    I live South of...
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    I did what Twin said two seasons ago, no leaks yet. Knock, on wood. Two seasons ago means about 2,000 to 2,500 miles.
     
  10. Apr 3, 2017
    jwmckenzie

    jwmckenzie Sponsor Sponsor

    Boston, MA
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    What specific brush on Sealer do you use?
     
  11. Apr 3, 2017
    jwmckenzie

    jwmckenzie Sponsor Sponsor

    Boston, MA
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    And the fix is?........
     
  12. Apr 3, 2017
    Twin2

    Twin2 wasn't me Sponsor 2019 Sponsor

    Virginia Beach, VA
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    jwmckenzie likes this.
  13. Apr 3, 2017
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
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    I just stuck a rubber o-ring in there, seems to be dry.

    H.
     
  14. Apr 3, 2017
    durangotang

    durangotang Member

    Western CO
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    Focker likes this.
  15. Apr 3, 2017
    mike starck

    mike starck Member Sponsor 2019 Sponsor

    salem,oregon
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    I have done two with a valve stem seal .This involves boring the speedo adaptor piece out and pressing the seal in .The second part is to fill the spiral grooves in the stem that goes thru the seal. I did this by brazing the grooves and then turning down smooth on the lathe.The second fix is easy and uses a O-ring on the stem before inserting it back into the adaptor. Long term I think the 7mm valve stem seal will be best.
     
  16. Apr 3, 2017
    mike starck

    mike starck Member Sponsor 2019 Sponsor

    salem,oregon
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    Yes I am sure that I didn't do anything that hasn't been tried before.
     
  17. Apr 3, 2017
    Jeepenstein

    Jeepenstein Me like Jeep.. Sponsor

    Middle TN
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    Yo
    u beat me to it..
     
  18. Apr 4, 2017
    Keys5a

    Keys5a Sponsor Sponsor

    Florida Keys
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    As far as the paper gaskets go, I like to use Permatex copper spray gasket sealer. I also use this product on head gaskets.
    -Donny
     
  19. Apr 5, 2017
    gotime

    gotime Sick with the car bug

    Minneapolis,...
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  20. Apr 12, 2017
    dieseljeeper

    dieseljeeper New Member

    spanaway, wa
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    Howdy, Ive had lot of rigs with d18 tc and what has worked for me has been #3 permatex on the paper gaskets and on both sides of each shim, locktite 545 on the bolts that see oil and RTV on the splines. Check the pan to make sure its flat and check the transmission mating surface at the bolt holes for cracks. If youre trying to cure a leak without disassembling it use rectoseal or thread tape on the pan and rear bearing retainer bolts. It is possible but they are manufactured to make it challenging to make them leak free
     

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