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Transfer box trouble - Who supplies parts?

Discussion in 'The Garage' started by Kiwi John, Aug 5, 2005.

  1. Kiwi John

    Kiwi John 1/2 ton status

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    Haven't had my truck long. It's an '83 K5 with 6.2L diesel. Some investigation reveals that i dont seem to have any drive to the front axle in High or Low. So I guess I have to strip the transfer box.

    Can anyone help with the following:

    # A parts diagram for the t.box It's a NP208C (small disc screwed to the rear of box has that on it NP = New Process?? )
    # Procedure for strip & rebuild.
    #Torque settings.
    #Who supplies parts for this box and would be willing to ship to me in England?

    Any thoughts / help would be gratefully received fellas.
    My internet access is 2-3 times a week so i will pick you up again on Friday. Thanks again.
    John
     
    Last edited: Aug 9, 2005
  2. Kiwi John

    Kiwi John 1/2 ton status

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    Can anybody point me towards a parts diagram for this box??
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    I should be able to have the parts manual scan up tomorrow.

    According to your description, I assume you have 2wd. It seems odd that you'd have 2hi and no other problems except no 4wd. Have you inspected the linkage from the shifter to the case to make sure they are operating correctly?
     
  4. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    I had the same problem. Turned out that I was missing the ring gear in my front axle. I thought it was my xfer case that was giving me 2wd only, then my rear driveshaft blew and I tried to limp home in 'front wheel drive', thats when my dad noticed the front driveshaft spinning, but I wasn't going anywhere. Jack up one front tire, put the case in Neutral, and see if the front DS spins when you spin the tire.
     
  5. Kiwi John

    Kiwi John 1/2 ton status

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    Hi Dorian. I havn't been able to check linkage operation on my own, Really need someone in the cab while i'm underneath i think.
    Shift lever goes into position for 4Hi and 4Lo but i tried a little wheelspin on gravel and only the rear wheels spun, thats why i think i've only got 2wd. Then the shift lever jumps into Neutral (between 4H & 4L) and when I put the trans shifter into neutral Or Park i cant shift transfer box at all. It just graunches in either direction and I have to switch engine off to shift back to 2H to get any drive at all.
    The cross member under the transfer box has a pair of bolts to the chassis on either side. The front pair of bolts have spacer sleeves between chassis rail and x.member. The rear pair of bolts are 'bare' and just seem to suspend the x.member from the chassis rail. Is this correct, do you know?
    Am kind of on my own out here and any help is very much appreciated. Thanks, John.
     
  6. Kiwi John

    Kiwi John 1/2 ton status

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    Thanks Matt. I'll try that at the weekend. I had the idea to put the whole truck up on axle stands and then i could see whether it was driving front and back axles but your method is a good start for sure.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Actually, the military already scanned it for us. :)

    Forgot about that until now. You'll need Adobe to view it, but the diagrams should be as good as the GM ones. Should be backside of pg 64-1.

    The parts listing is non-existent from what I can see though. If you need the parts list, I can scan in the GM one, but it won't be until tomorrow night.
     
  8. Blazer1970

    Blazer1970 1/2 ton status

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    Does your truck still have the factory automatic locking front hubs? If so, your problem is more likely with one or both of the hubs than with the transfer case.
     
  9. K5Jimmy

    K5Jimmy 1/2 ton status

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    I rebuilt my 241C, which is similar...I found an exploded view at www.motivegear.com you will have to drill around a bit to find it. They are wholesale only (sell only to dealers or someone who has a Tax Number identifying them as such)

    I bought my parts from www.nationaldrivetrain.com

    The bearing and seal kit for my 241c was about $110, new chain about $80, range fork about $55

    The disassembly/reassembly process is not difficult...you will need a good snap ring pliers, don't know what y'all would call them....snap ring spanner?

    It took me about an hour or so after I had the beast out of my truck.

    Cheers y'all
     
  10. Kiwi John

    Kiwi John 1/2 ton status

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    Thanks for the link Dorian. It is a big .pdf as you say and I'll havre to wait till tomorrow or Friday to look at it. I'll get back to you. Thanks again
     
  11. Kiwi John

    Kiwi John 1/2 ton status

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    Well It just looks original to me. Not sure what the hubs should look like tho. That's not as silly as it sounds cos there aren't many Blazers on the road here. i went to the biggesat Summer American car show last month and there were only 2 Blazers there, I hadnt found this problem at the time and I didn't take any notice of their hubs.
    How do 'automatic locking hubs work?
    How come I get this graunching noise trying to shift the x.box from N to 4L or 4H and I can feel the graunching thru the x.box shift lever?
    Not sure how that would be coming from the front axle if the auto trans is in P or N.
    I appreciate your thoughts.
     
    Last edited: Aug 10, 2005
  12. Kiwi John

    Kiwi John 1/2 ton status

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    The disassembly/reassembly process is not difficult...you will need a good snap ring pliers, don't know what y'all would call them....snap ring spanner?

    Thanks K5Jimmy. I really appreciate your input too. I'll look at the links in a minute.
    We call snap-rings "circlips", and would use "circlip pliers" to install/remove.
    I think the name comes from them being clips that fit around the circumference of another part. There are 'internal' and 'external' circlips.

    Any idea what oil goes in the 208? I was looking at old threads and there was a lot of discussion about gear oil and transmission fluid in x.box!
    John.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Auto hubs don't have knobs on them...you don't have to get out of the truck for 4wd. They have "4x4" stickers on them (IIRC) that match the stickers on the rear bolt on centercaps.

    Otherwise, you have "knobs" on the hubs that you twist to the "lock" position for 4wd.
     
  14. Kiwi John

    Kiwi John 1/2 ton status

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    No Knobs and yes to the 4X4 labels so they must be the Auto lockers?
    Do they freewheel when the drive shaft isn't turning if the x.box is in 2H?
    My previous experience with 4WD is on older Landrovers and the hubs were fixed drive. lockable hubs were an option only on them.
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Auto hubs need the truck to be driven in reverse to "unlock" them. Without that, and the t-case in 2wd, the front axles/driveshaft turn, but they are not being driven by the t-case front output.

    Yes they freewheel when unlocked completely. (again after being put in reverse)

    I don't know about the 208, but with my 205, the parasitic drag from all the components still allows the driveshaft to turn when driving, so it's a bit misleading to assume front driveshaft turning=power to front wheels.
     
  16. Kiwi John

    Kiwi John 1/2 ton status

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    Reverse

    Most informative!!
    What is the order of events here? To get from 4L or 4H to 2H do you reverse first then shift x.box, or shift the x.box then reverse? :confused:
    How far backwards do you have to go to unlock the hubs? (This is all new to me.)
    Sorry to sound stupid.
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    There is SUPPOSED to be a sticker on the backside of the drivers visor that tells you, but it's pretty simple. Put it into 2wd, and then back up. Common distance I heard was 15 feet.

    *IMO*, (well, quite a few lol) and not that you asked, but the auto hubs are complete pieces of junk and will fail you at the most inopportune time. They should really be junked unless you just don't care about having 4wd, and it sounds like you do. Personal experience with only two of these trucks so equipped has resulted in a 100% failure rate, with not hard usage.
     
  18. Kiwi John

    Kiwi John 1/2 ton status

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    Hubs

    You beat me to it!
    I was going to ask for your thoughts on the auto hubs.
    Do the manual hubs just bolt-on, or are there mods to the axle internals to be made?
    What type of hubs are best. WARN used to make lockable hubs to fit Landrovers. They were considered pretty good i recall.
    Sticker on visor tells me how to start diesel with glo-plugs,. Thats all it says.
    Apreciate your time Dorian.
     

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