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Strange transfercase

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ankarback, Aug 4, 2003.

  1. ankarback

    ankarback 1/2 ton status

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    I have a -76 blazer with a NP203. It has freewheelinghubs in the frontaxel to disconnect 4wd but what I understand about the NP203 that shouldn´t really work. The differential in the transfercase should put all the power on the axel with the least resistans wich would be the disconnected frontaxel and the truck shouldn´t move at all.

    The thing is that my truck works fine with this setup so I wonder if anyone have an idea what could have been done with the transfercase? I know it isn´t converted to part time or anything like that because it just have hi, and low to switch between not 2wd.

    Best regards

    /Johan
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    it has been converted to part time. none of conversion kits come with a stcker to put over the letters to tell you what is what.
    on the gear shifter it would be
    HI LOC
    HI
    N
    LOW
    LOW LOC

    when converted to part time it becomes
    HI 4wd
    HI 2wd
    N
    LOW 2wd
    LOW 4wd
     
  3. ankarback

    ankarback 1/2 ton status

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    I didn´t mean the letters. When you put the shifter forward you have 4wd low and backwards 4wd hi. I´ve looked at the front driveshaft and it´s always moving even if you release the freewheelinghubs.

    /Johan
     
  4. ankarback

    ankarback 1/2 ton status

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    Anyone?? How is the NP203 working. Should it work with freewheelinghubs.

    /Johan
     
  5. gravdigr

    gravdigr 1/2 ton status

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    a stock np203 can NOT work with open hubs unless it is in loc. Your case has been part timed. There is still some parasitic drag on the front driveshaft with the part time kit so while the vehicle is moving it will seem that the shaft is turning but it isn't driving.
     
  6. ankarback

    ankarback 1/2 ton status

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    OK, something has to been done to it then. The strange thing is that I don´t have that many options for the shifter and I don´t mean the letters. As I described I just have two ways to put it, forward or backwards and if I lock the hubs I have 4wd either way.
    Could the tranfercase been modified so its always in "loc" or is it just broken :-).
     
  7. gravdigr

    gravdigr 1/2 ton status

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    is the shifter adjusted properly? There should be 2 rods going from the shifter to the T case, one controls high or low range and the other controls 4wd and loc. I guess it is possible the PO removed the 4wd and loc linkage leaving it in loc, and only left the hi lo linkage connected. That would give you 2 ranges but is not part time 4wd since the t case and front shaft are still moving. It is also my understanding the running in 4wd with unlocked hubs is BADtm. Crawl under and look at the side of the T case where the shifter is. You can also remove the floor hump over the tranny if you need to. If there are not 2 linkages going from the shifter to the t case then that's your problem. You are positive this is a NP203 case?
     
  8. ankarback

    ankarback 1/2 ton status

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    Thanks for the help gravdigr. I´m going to check the linkage tonight. That´s probably what´s done with it.
    The PO has done a lot of strange thing with the truck so I´m not surprised if he did that too.
    Do you know wath could happend if I drive it like it is in 2wd?
     
  9. gravdigr

    gravdigr 1/2 ton status

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    actually, I do not know. I was just always told never run 4wd with the hubs unlocked or bad things would happen, but no one ever told me what bad things /forums/images/graemlins/tongue.gif
     

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