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NP 203 keeps slipping out of 4lo

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Mudzer, May 15, 2000.

  1. Mudzer

    Mudzer 1/2 ton status Author

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    My NP 203 has the Mile Marker part time kit (spider gear replacement) and has been slipping out of 4lo. When it slips out, I am in 2 wheel lo. Any Suggestions? I have an NP 205 that needs some work done, how hard is it to convert? Plus what years did the NP 205 have the slip joint in the rear. I am not sure if mine has it or not. Thanks.

    <font color=red>Mudzer</font color=red>
    1978/91 K5 Blazer
     
  2. Depdog

    Depdog 1/2 ton status Author

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    We'll, it's most lilkely slipping out because the shifter is not adjusted right, the 203 has some weird linkage and if its not right it will do what is happening to you and usually when you put it in reverse it goes into 4wd because of vacume in the case. The 205 is less prone to breakage and problems, but you are going to have to change allot, the adapter between the tranny and t-case, the rear shaft will have to be lengthened, and possibly the front shaft shortened.

    Not sure about the slip joint, but if you look at the rear of you t-case if it does not have a coned tail housing with a shaft that does not have any threaded end to accept a large nut then you have one.

    Depdog

    <font color=blue>"Lead, Follow, or BECOME the Trail"</font color=blue>
     
  3. blazer72

    blazer72 1/2 ton status

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    The cost of replaceing the 203 with any thing is to much unlees you have a good reson !! The 203 is as strong as the 205 any way You may have to rebuild but even thats not to costly Is it slipping out of gear all the way If so there is a good detent in the range box thats very easy to reagust the shfter too!
     
  4. Eric78K5

    Eric78K5 1/2 ton status

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    Mine had the same problem. Just adjust the linkage, and it'll be fine. I don't have the part time conversion, mine is still full time.
     
  5. Waxer

    Waxer 1/2 ton status Author

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    My 203 had the same god damn problem. I adjusted the shifter many many times to no avail, then I had the sucker rebuilt and it still did it. I finally wised up and installed a freshly rebuilt NP205. I had to purchase the adapter from www.standardtransmission.com for $100, bought the gaskets from the dealer for about $10, I did however have to get the rear shaft lengthened and the front shaft shortened, that cost around $80. The final result is a bulletproof case that STAYS in 4low until I take it out of 4 low.
     

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