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ATF leaking from rear of transfer case/ Poly-urethane trans. mounts?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BayouBlazer88, Feb 13, 2003.

  1. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    Not too long ago, BowiteBlazer and I yanked out my auto tranny and transfer case to replace my rear main engine seal. Now ever since I put it all back together, there seems to be a slow ATF leak coming from the U-joint closest to the T-case. Is there a seal in the T-case that I busted and need to replace or what?

    Also, on another note, I was reading several of the old posts about polyurethane bushings and how they are great for body mounts but not for suspension mounts on trucks. I'm about to buy a set of energy suspension body mounts since my stock rubber ones are shot. So my question is: Are the polyurethane transmission mounts worth it as well? Or should I just replace it with an OEM mount? Thanks

    Matt
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    You have to go poly engine/trans mounts, or rubber on both. You can't mix and match.

    Well, you can, but you'll break the adapter.
     
  3. Hossbaby50

    Hossbaby50 3/4 ton status

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    For the tcase, you can try and replace the rear seal on the NP208. It isn't hard. Pull the driveshaft and then pry out the old seal. Tap then new seal in. But it probably won't solve the problem. I replaced my real seal, and it still leaks. I have just gotten used to it leaking.
     
  4. ColAdo82K5

    ColAdo82K5 1/2 ton status

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    Hey,
    I replaced my rear slip yoke seal and it did great. It might just be the original one in there. And after playign with it taking the rear shaft out...it messed it up...no big deal. No pullers are involved just pry out straight out and tap new one in.
    Blake
     
  5. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    Ok, that sounds easy enough. Are you 2 guys talking about the same seal? And is there something that could break in the T-case if my ATF fluid gets to low? thanks guys.

    Matt
     
  6. 70~K5

    70~K5 1/2 ton status

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    There's lots of things that can go wrong if you run the fluid to low or to high.
     
  7. Hossbaby50

    Hossbaby50 3/4 ton status

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    Yep, we are talking about the same seal from what I can tell. If that doesn't stop your leak though, it is something farther up in the tcase that is harder to get to. I haven't gotten around to changing mine, so I don't know how hard it is. But I know for alot of people that the seal isn't the problem, but you might be lucky and thats all it is. It is only a few $ for the seal, and doesn't take that long to do. Try it and see. Also note that when you pull the rear shaft it is going to leak tranny fluid out, so be ready for that, and make sure you refill the tcase afterward.

    Harley
     
  8. the professor

    the professor 1/2 ton status

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    If the seal between the transfer case and the trans leaks, it will leak trans fluid into the transfer every time the vehicle sits, and the converter drains back into the transmission
    --
    It will leak, even if the trans fluid is lo..so overfilling the trans would have no effect on a normal seal
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    It substitutes for the "slip-yoke" seal on a 2wd
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    Eventualy, the transfer case will fill up with ATF (not a good thing on a NP205)..causing it to leak, and also increase power drag, because it is overfull
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    The adapter for a NP205 (or 203), accepts two seals for the connecting collar, (one with the backside to the trans, and one with the backside to the transfer) and has an 'O'-ring sealing the connector to the NP input shaft
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    The 208 has no 'O'ring and only has one seal... /forums/images/graemlins/cool.gif /forums/images/graemlins/truck.gif
     
  9. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    Again...I think its that pesky little hole in the rear yoke that fluid has been rumored to seap through at times...we can change the seal first though...thats a 10minute job, come on now, I've rebuilt a t-case why couldn't we just replace a little seal? /forums/images/graemlins/smirk.gif
     
  10. caryhenry

    caryhenry Registered Member

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    I had this same problem on mine, and it WASNT the transfer case output seal. The leak was coming from a plug in the slip yoke itself. To see if that's where it's leaking, take the driveshaft off and clean the back of the slip yoke by the u joint. Then smear some rtv sealant around the slip yoke plug. I did this rather than removing the slip yoke cause I didn't want to replace my ujoint, and it hasn't leaked for 4 months.
     

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