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Rear TC seal on 208 leak

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by txbartman, Jun 22, 2001.

  1. txbartman

    txbartman 1/2 ton status

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    For a while I have been noticing a fine misting of oil on my back window after driving on the highway. Under the truck, I have a nice spray line right above the u-joint of the TC output shaft and the rear driveshaft. My guess is that my rear TC seal is leaking. If I drop the driveshaft and pull the output shaft from the TC to change the seal, will I loose a bunch of fluid from my TC? Or does it not fill that high?

    85 GMC Jimmy, 305 w/TH700-NP208, 32X11.5 BFG ATs, 15x10 Eagles, Smittybuilt tube nerf bars and bumbers
     
  2. Emmettology 101

    Emmettology 101 3/4 ton status

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    If you pull the d-shaft out you may loose some. THis would be a good time to change the fluid if you haven't done so recently.

    Onceyou pull the d-shaft uout, pull the rear seal out and pop the new one in.

    There was talk awhile back that there is a small hole that can become unplugged in the rear d-shaft yoke and the fluid may be sneaking out of that.

    <font color=green>MIKE</font color=green> - "Hukd on fawnics,werkd fer me!"
    <A target="_blank" HREF=http://www.geocities.com/emmettology101>http://www.geocities.com/emmettology101</A>
     
  3. 1986Blazer

    1986Blazer 1/2 ton status

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    OK....while we are on this topic - I have the same problem. I replaced the seal on the TC but the leak still happens. If this plug in the yoke is open - what needs to be done to close it! Has anyone done this repair?



    <A target="_blank" HREF=http://www.geocities.com/keywestk5/KeyWestK5.html>http://www.geocities.com/keywestk5/KeyWestK5.html</A>
     
  4. bigblue

    bigblue 1/2 ton status

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    I have come to the realization that maybe these 208's just plain LEAK. I have had it resealed twice this year ( luckily under warranty ) and replaced the seal and it still leaks. Whatever just top off and go...
     
  5. txbartman

    txbartman 1/2 ton status

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    Where is this plug? How could I inspect mine to see if it is unplugged. I hate leaks. Especially ones that get oil on the back of my truck.

    85 GMC Jimmy, 305 w/TH700-NP208, 32X11.5 BFG ATs, 15x10 Eagles, Smittybuilt tube nerf bars and bumbers
     
  6. Emmettology 101

    Emmettology 101 3/4 ton status

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    E-mail or call Jesse at High Angle Driveline! I believe he is the one that shed the light onthis subject!

    <A target="_blank" HREF=http://www.highangledriveline.com>http://www.highangledriveline.com</A>

    <font color=green>MIKE</font color=green> - "Hukd on fawnics,werkd fer me!"
    <A target="_blank" HREF=http://www.geocities.com/emmettology101>http://www.geocities.com/emmettology101</A>
     
  7. FRIZZLEFRY

    FRIZZLEFRY 1/2 ton status

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    You can seal up the plug on the back of the yoke with JB weld.Just make sure its clean and dry before you put it on.I did this to mine a few years ago to stop a leak.

    <A target="_blank" HREF=http://community.webshots.com/user/beaterwhang>http://community.webshots.com/user/beaterwhang</A>
     
  8. Emmettology 101

    Emmettology 101 3/4 ton status

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    I have never actually seen it, but if you pull the d-shaft ad look down into the splined part of the yoke, I believe it is directly in the center at the bottom. Or you may be able to see it on the outside.

    Give Jesse at high Nagle Driveline a call, he can better explain this: <A target="_blank" HREF=http://www.highangledriveline.com>http://www.highangledriveline.com</A>

    <font color=green>MIKE</font color=green> - "Hukd on fawnics,werkd fer me!"
    <A target="_blank" HREF=http://www.geocities.com/emmettology101>http://www.geocities.com/emmettology101</A>
     
  9. FRIZZLEFRY

    FRIZZLEFRY 1/2 ton status

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    Where does yours keep leakin Blue?Are they using gaskets or Permatex?I resealed the case halves and the extention housing with Permatex 5 or 6 years ago and its stayed dry.If the rear seal keeps leaking you might need a new extention housing bushing.

    <A target="_blank" HREF=http://community.webshots.com/user/beaterwhang>http://community.webshots.com/user/beaterwhang</A>
     
  10. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    I found out that it is the seal at the rear output shaft that leaks. Now you can go and put 100's of those things on and it won't stop that leak. The secret is to put some Teflon pipe thread sealer around the outside metal part of the seal. It comes in a tube and has the consistency of wood glue. You put it on the part of the seal that makes a metal on metal contact with the T-case. I got some of this sealer from the GM dealer, it works great.
    It also stopped the leak.

    '83 GMC Jimmy 4x4 ZZ4 Crate Motor
    '83 Chevy P/U 4x4 Sand Drag Racer, 578 RWHP
    '94 Impala SS
    '01 Chevy 2500HD w/8.1L & Allison Auto
     
  11. OneInTheSun

    OneInTheSun 1/2 ton status

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    Regarding the weep hole in the yoke, I was under the impression that it wasn't a good idea to seal it up. If it's sealed, what accounts for the pressure change when the yoke/shaft slides in/out of the transfer case? I know there was discussion on this a while back but can't remember if it came to a sound conclusion. Since I'm in this predicament right now, I ask, "To seal or not to seal?"

    <font color=blue>Rob
    85 K5</font color=blue>
    [​IMG] 24 beers in a case, 24 hours in a day - Coincidence?
     
  12. bigblue

    bigblue 1/2 ton status

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    Man it leaks from the rear seal and the case halves....I am moving soon to a place with a garage. Once I do this I will takethe sucker taken apart and fixe it right. Permatex huh ? Is that some special kind of sealant ?
     
  13. newyorkin

    newyorkin 1 ton status

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    I had the same trouble right after I got my truck, but it turned out to be the dipstick grommet got torn up. Turned out fluid from the grommet ran along the top of the tranny and looked like it was coming from other places. I had identical symptoms, and one night it peaked. I lost all my tranny fluid, practically as I poured it in.

    Here's what it looked like when I finally got it home:
    http://k5.8m.com What more is there to life?**<P ID="edit"><FONT SIZE=-1>Edited by newyorkin on 06/24/01 10:23 AM (server time).</FONT></P>
     
  14. HarryH3

    HarryH3 1 ton status Author

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    Gotta add "rl" after the "u" when you put in the tags to make a URL. Like this:
    <A target="_blank" HREF=http://k5.8m.com/cgi-bin/i/images/Dipstick/bleedingtranny.jpg?back=2>http://k5.8m.com/cgi-bin/i/images/Dipstick/bleedingtranny.jpg?back=2</A> [​IMG]

    Make sure all of the bolts are tight on your 208. The bolts that hold it in place thread into the interior of the case. If they aren't tight, then ATF will leak past the threads and make quite a mess. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://www.angelfire.com/super/ThunderTruck>http://www.angelfire.com/super/ThunderTruck</A>
    It's a great day to be alive...
     
  15. FRIZZLEFRY

    FRIZZLEFRY 1/2 ton status

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    Permatex is like RTV silicone .Ive also used stuff called formagasket.The best stuff I have found I got when I worked at Ford. It was a Ford part# but had International on the tube .It was used for sealing different stuff on the 7.3 DIT Powerstroke engines.Ford also makes stuff called gasket eliminator. It looks like purple lock tite .The key to using both is having a clean ,dry surface when you apply it.

    <A target="_blank" HREF=http://community.webshots.com/user/beaterwhang>http://community.webshots.com/user/beaterwhang</A>
     
  16. jarheadk5

    jarheadk5 1/2 ton status

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    If you've already changed the output seal, it's probably the slipyoke itself leaking. As I understand it, the yoke portion is pressed onto the shaft, resulting in occasional leaks from there. Mine is currently leaking from there, too. I have a replacement slipyoke that I'll be cleaning up, and I'll CAREFULLY put some JBWeld inside the splined shaft to seal the yoke to the shaft.

    <font color=red>Click those banners and help support CK5!!<font color=black>
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  17. Itali83

    Itali83 1/2 ton status

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    Is it true that there is a bushing at the rear of the 208 that the slip yolk rides on?? if that is true, then if that wears out, you will put seal after seal on it and you will never stop the leak. Mine leaks but leavs now puddles and I've put 2 seals in it in the last 2 years, and none have acually stopped the leak. So maybe I think the bushing is getting a little worn making it leak. Just my idea.
    Ben 87 Jimmy
     
  18. FWP

    FWP CRS

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    Ben, you are absolutely correct. The bushing in the tailhousing wears out, the slip joint wobbles, and wears out the seal......

    <A target="_blank" HREF=http://fwp4x4.rockcrawler.com>http://fwp4x4.rockcrawler.com</A>
     
  19. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I think mine leaks too. I don't even care. I just top off and go. I'm not the only one I know either. Everyone I know that has a 208 has had some leaking problems at one time or another. One in particular was really bad.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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