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Transfercase oilchange

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ankarback, Dec 2, 2002.

  1. ankarback

    ankarback 1/2 ton status

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    Hi

    Just bought a -76 Blazer K5 and I´m wondering what kind of oil i should use in the tranfercase (NP 203).
    The car is used a lot in mud and water so some maintainance i really nessesary.

    Best regards

    /Johan
     
  2. beater74

    beater74 1/2 ton status

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    plain old 10w30 /forums/images/graemlins/grin.gif
     
  3. ankarback

    ankarback 1/2 ton status

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    OK, thanks! Good that I didn´t used 75/90 for it.
     
  4. Pookster

    Pookster 1/2 ton status

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    is it the same for a 205?

    Where's the stinkin fill hole?? And please dont tell me where the cable goes in. /forums/images/graemlins/smile.gif
     
  5. beater74

    beater74 1/2 ton status

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    nope a 205 uses gear lube 70/90 , just like you put in yer diff.
     
  6. MJF

    MJF 1/2 ton status

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    So:
    NP203=10W30
    NP205=90wt
    NP208=tranny fluid
    NP241(or whatever else they put in K5's)=?

    Are the top three right? What about the other?
     
  7. blazerman78

    blazerman78 Registered Member

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    Dies it really matter if gear lube is used in it? Mine has gear lube in it (I bought it that way) and it seems to work. Also, it's been converted to part-time, if that matters.
     
  8. txbluethunder

    txbluethunder 1/2 ton status

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    241 is the same as the 208, dextron III atf
     
  9. 74Chev

    74Chev 1/2 ton status

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    DO NOT USE GEAR OIL. The 203 must use 10-30 motor oil. To drain the unit pull the lower bolt on the cover on the back of the case. To refill squirt the oil into the fill hole halfway up the case. 80-90 + 203= kaboom.
     
  10. 74Chev

    74Chev 1/2 ton status

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    The NP 205 uses 80w-90 gear lube. The fill plug is on the back halfway up the case and can be removed with a 9/16" open end wrench. Fill the case not more than 1/2" below the fill hole. You can squirt the oil in with a bottle or buy a pump, or go to the local quick lube and pay 19.95 to do a drain and fill service.
     
  11. imiceman44

    imiceman44 1 ton status

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    I have used gear lube in my 203 for more than 10 years, had no problems, the chain never stretched and everything was very silent.
    I don't see a problem running gear lube in it, except the drag, which I didn't feel.
     
  12. 4x4Freak

    4x4Freak 1/2 ton status

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    I've heard that gear oil in a 203 will cause the chain to wear out faster. I think it may also damage the oil pump.
     
  13. imiceman44

    imiceman44 1 ton status

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    What oil pump?
    I rebuilt the 203 when I bought the truck, there was no pump.
    And I reused the chain that was in it, and it had gear lube.
    It was a 1 ton 203 though, with a one piece tail housing all cast iron, no aluminum parts.
     
  14. 4x4Freak

    4x4Freak 1/2 ton status

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    np203 oil pump

    The part about the chain wearing out faster is just what I have been told, I have no evidence of this being true. All I know is that my 205 is a lot stronger than my old 203.
     
  15. Redfrog

    Redfrog 1/2 ton status

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    it is a little disc the looks like it has been threaded and goes on the output shaft it pumps oil to the rear out put bearing
     
  16. imiceman44

    imiceman44 1 ton status

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    Oh that's a pump? well it was fine, and I never changed it.
    By the way, gear oil is just thicker and slicker, so wear would be less on everything.
    The type of pump this one has doesn't get affected by thicker oil, since it's not the sealed type ie: not compressing the oil, just sling it and making waves.
    The chain was more than 20 years old, and I kept it and I drove it hard in a full time configuration for 5 years after that.
    Believe me it's much smoother and I don't care about the parsitic losses ( drag from the thickness of the oil), if I did I wouldn't put 35" mud tires on it /forums/images/graemlins/smile.gif
     

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