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what the hell?!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 73/75 k5, Apr 12, 2000.

  1. 73/75 k5

    73/75 k5 Registered Member

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    today I went to check my fluid level on my 205 transfer case and when I pulled the filler plug out, out came a gushing flow of tranny fluid. Do I need to rebuild my t-case or tranny? Did possibly a rear seal bust on my tranny? Help! This is the first time I've seen this.
    Any info would be greatful
    Thanks
     
  2. Boss

    Boss 1/2 ton status Author

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    I use ATF fluid in my Transfer case. Its a NP205.
    Dexron III was the type. NP205 is suppose to use ATF fluid. That is probably why you had it in there.
    Boss
     
  3. IDGMC

    IDGMC 1/2 ton status

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    I may be wrong but i thought a Np205 used gear oil? My Np208 used ATF and so did my Np203. Anyone know for sure?
    And if it is pouring out of the fill hole it sounds like there is a problem how would you fill beyond that point?
     
  4. dpearson

    dpearson Registered Member

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    Are you sure it is supposed to be ATF in the 205, I have heard it both ways. Need to know for sure?
     
  5. Burt4x4

    Burt4x4 3/4 ton status

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    My 205 uses 90WGear Oil!

    Rock ON![​IMG] 72 K5 [​IMG]
     
  6. Boss

    Boss 1/2 ton status Author

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    ok, I didn't read it right. I didn't see the part that you said it is gushing out your filler hole. My bad, now that sounds like a problem. I would assume your tranny is leaking into your transfercase. But I hear it does leak from time to time and that is ok if small amounts b/c the NP205 uses ATF. And YES, it is suppose to use DexronIII. formerly Dexron II. And YES, you can use gear oil too.
    Now, for IDGMC, man, you put ATF in your NP203??? NP203's are suppose to use Motor oil, not ATF. I'm am almost 100% on that, but I do not own a 203 so I can't back it up. Someone correct me if I'm wrong.
    Boss
     
  7. AZK5

    AZK5 1/2 ton status

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    NP203=motor oil
    NP205 w/MT=gear oil
    NP205 w/AT=ATF
    NP208=ATF
    NP241=ATF
    Your transmission is probably leaking into the transfercase. You can fix that seal or you can regularly add ATF to your tranny and drain some from your transfercase.
    CB
     
  8. Blazer79

    Blazer79 1/2 ton status

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    Yup, the NP203 uses 10W-30 engine oil. I have one still full time on my Blazer. Over 105K miles and still running fine.

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  9. I know I'm not answering but, where exactly is the filler plug for a 203?

    <font color=red>ABO</font color=red>
     
  10. Steve88

    Steve88 1/2 ton status

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    Stupid question, but have you checked your tranny fluid level now? If the fluid came gushing out of your t-case, and your tranny is still reading full ... ??

    <font color=red>Steve88</font color=red>[​IMG]
    88K5 Silverado
    thunderdog@metallica.com
     
  11. BlueKnight

    BlueKnight 1/2 ton status

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    Motor oil in a 203? Oh Boy I need to check and see whats is in there. I think its gear oil.

    <font color=purple>79' K-5 396cid 600hp, TH350, NP203</font color=purple>
    http://79blueknight.homepage.com
     
  12. dpearson

    dpearson Registered Member

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    I bought a used 205 without oil. It is going behind an Automatic, are you sure I use ATF, it currently has gear oil, will either one be bad for it?
     
  13. AZK5

    AZK5 1/2 ton status

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    You can run either ATF or gear oil in the NP205. If your AT leaks a little into the transfercase then it would be better to have ATF in it. Otherwise you would be mixing ATF and gear oil.
    CB
     
  14. Thumper

    Thumper 1/2 ton status

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    I really like gear oil in mine more than ATF... Ive never heard of anyone running tranny fluid in one so Im sticking to what the majority uses!

    Mike'


    <font color=blue>Thumper
    85 Fullsize Jimmy
    [​IMG]
    <font color=red>Lets Go Wheelin! </font color=red>
     
  15. Boss

    Boss 1/2 ton status Author

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    Gear oil is fine, but ATF is better. Dexron III is the preferred choice. B/c your tranny will sometimes leak into the transfer case, so why not have ATF leak into ATF instead of ATF leak into Gear oil.
    Boss
     
  16. mudfanatic

    mudfanatic 1/2 ton status

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    I had this problem start on my NP 231 after my transmission was replaced (S10 Blazer), turns out that the input seal in the transfercase started leaking after the transmission was pulled out and reinstalled. It is probably the input seal on your transfer case. relatively simple job.
    '77 K5

    <font color=red>mudfanatic</font color=red>[​IMG]
     
  17. RaisedK5

    RaisedK5 1/2 ton status

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    Just to add my two cents, the 1974 Factory Service manual calls for 30w in a 203, not 10w-30, its supposed to be a straight weight not a multi-weight

    RaisedK5

    "Friends don't let friends drive Fords"
     
  18. Blazer79

    Blazer79 1/2 ton status

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    The filler plug is on the rear of the case, to the right of the rear driveshaft output (your right hand if you're facing the rear of the transfer case). It's a large plug (9/16" maybe?) that you can't miss. It's a little high in the case. Just fill it up until the oil starts to pour out.

    There's no plug to drain the old oil, so you'll have to remove the lowest bolt of the ones that are in a circular pattern. Remove the skid plate in order to prevent a (even larger) mess.

    I won't take credit for that. I learned it from some wonderful guys at a wonderful site called ColoradoK5.

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  19. Blazer79

    Blazer79 1/2 ton status

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    I visited Shawn's link about oils. Now I know that 10W means that it will be like a 10 grade in Winter. Since I'm in hot weather, I think that the oil will act as 30 grade most of the time, so I guess I'm safe, or not?

    Does your manual mention anything about how often should this oil be changed?

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     

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