Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

tranny fluid leaking into 205t-case

Discussion in 'The Garage' started by k2-k5, Oct 21, 2004.

  1. k2-k5

    k2-k5 1/2 ton status

    Joined:
    Sep 30, 2003
    Posts:
    285
    Likes Received:
    1
    Location:
    Vancouver, WA
    Th350 to a NP205 transfer case. Transfer case fluid is a mixture of 90wt and transmission fluid. Anyone know what seal needs to be replaced to prevent transmission fluid frm getting into the t-case.

    Thanks
     
  2. OLD DAWG

    OLD DAWG 1/2 ton status

    Joined:
    Jul 20, 2002
    Posts:
    444
    Likes Received:
    0
    Location:
    MONTROSE, COLORADO
    Sounds like the seals in the adapter are bad. Make sure to check the connector as well they will get grooves in them over time.
     
  3. k2-k5

    k2-k5 1/2 ton status

    Joined:
    Sep 30, 2003
    Posts:
    285
    Likes Received:
    1
    Location:
    Vancouver, WA
    The connector??
     
  4. BobK

    BobK 1/2 ton status

    Joined:
    Oct 5, 2000
    Posts:
    1,604
    Likes Received:
    0
    Location:
    Petrolia,Ontario,Canada but working in Port Huron,
    that happened to me as well.I replaced the seal in the trans to T/C adaptor.
    I think there is one on each end,Trans side and T/C side.
     
  5. like_a_rock

    like_a_rock Newbie

    Joined:
    Oct 7, 2004
    Posts:
    3
    Likes Received:
    0
    Location:
    WA, USA
    actually, some tranny's and t-cases are ok to do that. I would double check and make sure that your t-case is supposed to have gear lube in it. chevy new that that would happen that's why they made their t-cases to take tranny fluid. find a book or a computer that will tell you waht is supposed to be it your t-case b/c there's a good chance it's supposed to be tranny fluid. mine does the same thing. and if you do choose to keep gear lube in the t-case than you need to find the right seal that is meant to keep them seperate, stock seals won't. /forums/images/graemlins/thumb.gif
     
  6. ntaj*ep

    ntaj*ep 1/2 ton status

    Joined:
    Feb 4, 2002
    Posts:
    3,248
    Likes Received:
    1
    Location:
    Evergreen state
    [ QUOTE ]
    actually, some tranny's and t-cases are ok to do that. I would double check and make sure that your t-case is supposed to have gear lube in it. chevy new that that would happen that's why they made their t-cases to take tranny fluid. find a book or a computer that will tell you waht is supposed to be it your t-case b/c there's a good chance it's supposed to be tranny fluid. mine does the same thing. and if you do choose to keep gear lube in the t-case than you need to find the right seal that is meant to keep them seperate, stock seals won't. /forums/images/graemlins/thumb.gif

    [/ QUOTE ]

    NP 205 t-cases use gear oil and only gear oil.

    There is an o-ring on the sleeve inside the adapter that is usually the problem. I went through about 3 or 4 till I found the right one. I think everyone is different and you need to make sure yours has a tight fit before you put it back together. I tried to blow through mine before I put it back together, took a few min. to get the ATF taste out of my mouth but worth not having to replace all the seals in my t-case for sure....
     
  7. k2-k5

    k2-k5 1/2 ton status

    Joined:
    Sep 30, 2003
    Posts:
    285
    Likes Received:
    1
    Location:
    Vancouver, WA
    Wish you a part number of the right one.

    In one of my other blazers the same thing was happening and tranny fluid would keep flowing into the transfer case until it was blowing out the seals. I had to keep draining fluid out of the fill plug on the transfer case until I fixed it.
     
  8. bigblock44k5

    bigblock44k5 1/2 ton status

    Joined:
    Jun 8, 2003
    Posts:
    396
    Likes Received:
    0
    Location:
    Hurlburt Field, FL
    Not sure how many seals are in a 350 to 205 adapter, my 465 to 205 adapter has 1 seal. Gear Fluid only in a 205, 208's can take it as well, they went to atf in 208's for improved mileage i believe, could be wrong.
     
  9. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    I did mine last weekend with some help...

    I have the part # somewhere...let me look for it in the daylight and get back to you. I got them from NAPA. They had 2 in stock. I brought in the old seal and cross ref'd the # on it to get a new one (no books seam to have the right # in them...the ones I bought before I opended it up didn't fit).
     
  10. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    The part # for the seals in the adapter between my '71's th350 & NP205 is 19760. I got them at NAPA which means it was chicago rawhide brand. They were $6.97 each. One of them was whatever brand they used to cary but with the same part #.
    /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif

    Have fun getting the 205 out! It is one heavy awkward sucker! It took 2 people most of the day just to change those 2 seals out. Be warned there will be about 2 quarts of tranny fluid that won't drain out that will come out (right onto my driveway /forums/images/graemlins/doah.gif) when you crack the adapter off the trans. I didn't have room for a drip pan because the tranny jack was in the way so it just made a huge mess /forums/images/graemlins/mad.gif
     
  11. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    1 more thing.
    NAPA's front output seal sucked. Look for another brand at AutoZone or something. You don't want the CR brand. You might as well replace that seal while you are at it. Mine leaked bad. The t-case being full of ATF about 1foot above the fill plug didn't help /forums/images/graemlins/screwy.gif
     
  12. k2-k5

    k2-k5 1/2 ton status

    Joined:
    Sep 30, 2003
    Posts:
    285
    Likes Received:
    1
    Location:
    Vancouver, WA
    Awesome. Thanks for looking into that for me.

    I managed to take out my transfer case and th350 togther as one unit. Thought that it would be easier to balance that way. Wasn't to bad other then the bellhousing catching on the headers. I hate headers.
     
  13. Triaged

    Triaged 1/2 ton status

    Joined:
    Feb 21, 2001
    Posts:
    3,808
    Likes Received:
    0
    Location:
    CA (LA/OC area)
    I found that the easiest way to remove/install the th350/np205 is to leave them together and drop them down from the top with an engine hoist. The tranny hump unbolts and if you wrap a chain around the adapter it will balance with pinky pressure. It leaves you alot more room under the truck to move around.
     

Share This Page