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Thread: Transfer case question

  1. #1
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    Default Transfer case question

    Not sure where to post this question.
    I have a 99 chevy suburban k2500 with a 4l80e tranny I just had swapped out. but now I am in need of getting the 4x4 transfer case working. It will not engage into four wheel drive when I push the button on the dash. The light will blink but never stay solid other then in 2wd. I have checked fuses and connections and not luck. Just wondering if there are schematics/troubleshooting guides out in the world for this or any advice on how to check it? I believe (haven't verified yet) that it is a NP241C transfer case if that helps. I will climb under it tonight after work to verify. Thanks agian and sorry if in wrong thread just let me know.
    Regards,
    Brian

  2. #2
    Joe (Moderator) joecar's Avatar
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    I have year/model that in the Service Manual... what engine...?

  3. #3
    Joe (Moderator) joecar's Avatar
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    This is from the 7.4L... if this is the right one, I can paste any troubleshooting I see in the manual.
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  4. #4
    Senior Member JustinD's Avatar
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    Its the motor on the Tcase. Replace it.
    2001 Chevrolet K2500HD Duramax
    Suncoast SCIV 1056
    Kennedy twin lift pumps
    Billet pick up
    MBRP 4" exhaust
    Air intake horn mod
    ARP head studs
    A few more go fast/truck pulling goodies!
    Tuned with EFI
    12.65 @ 107 1.71 60'

  5. #5
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    It is a 7.4 liter motor.
    Where is a good place to purchase that motor? Napa? Autozone? Etc.?

    This is just a bolt on and go thing right? Not calibration or linkage adjustment needed?

  6. #6
    Joe (Moderator) joecar's Avatar
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    Service Manual says "no transmission documents found for 1999 Chevy Suburban".

  7. #7
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    Over the THanksgiving holiday I was able to tinker around with this t case. I was under the suburban and had my daughter push the button for the 4wd and I could hear the motor at the Tcase actuate but the acuator on the front axel did not move. So it is either the wire cable to the front axel or the actuator it self. I am just trying to figure out now what wire is what to check to see if it is sending the signal or not or if the front actuator is needing replaced. Thanks for the schematic Joecar! I will study it this week and maybe this weekend get back under if time permits.

  8. #8
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    I went ahead and replaced the front Diff actuator for the 4wd and still nothing has changed. I will have to look deeper into the tcase I think. But for the life of me I still can't understand why everything can't work. I have changed the push button switch on the dash. I have heard the motor working on the Tcase when the buttons are pushed and now the front actuator has been changed but still not working... Does anyone know the sequence in which all the components are suppose to work in order the other items to engage? Thanks!

  9. #9
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    The motor on the tcase seems to be working. When the 4hi is pushed the front drive shaft locks into place but the front axle does not engage. Now I am looking for a scan tool to locate codes for the Transfer Case Control Module. How much are these tools? Which brand are reliable? Or is it just better to take it to a dealer and have them troubleshoot these issues?

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