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76 Chevrolet 1/2 Ton Questions

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bga, Jun 7, 2004.

  1. bga

    bga Registered Member

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    I did quite a bit of searching but could not find anything. I believe my problem lies with the terms used.

    I just purchased a 1976 Chevrolet 1/2ton 4X4 truck. 12 bolt rear, Dana 44 front, full time 4 wheel drive. I have a couple of questions if someone has the time.

    Am I correct in assuming that the transfer case is an NP203 since it is a full time unit?

    With this full time setup, how do the front hubs come into play? Are these actually locked at all times, and the transfer case actually locks and unlocks the front axle?

    Without considering mileage concerns, could this setup be reliable after being rebuilt? I don't plan to change the full time setup since it fill fit my needs as it is, as long as it is strong and reliable.

    Was there a factory option for PosiTrac on this truck? It seems both front and rear axles have some sort of PosiTrac unit, I just thought I'd ask before I get to the point of rebuilding the axles.


    Thanks for your time!
     
  2. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    I did quite a bit of searching but could not find anything. I believe my problem lies with the terms used.

    I just purchased a 1976 Chevrolet 1/2ton 4X4 truck. 12 bolt rear, Dana 44 front, full time 4 wheel drive. I have a couple of questions if someone has the time.

    Am I correct in assuming that the transfer case is an NP203 since it is a full time unit?

    With this full time setup, how do the front hubs come into play? Are these actually locked at all times, and the transfer case actually locks and unlocks the front axle?

    Without considering mileage concerns, could this setup be reliable after being rebuilt? I don't plan to change the full time setup since it fill fit my needs as it is, as long as it is strong and reliable.

    Was there a factory option for PosiTrac on this truck? It seems both front and rear axles have some sort of PosiTrac unit, I just thought I'd ask before I get to the point of rebuilding the axles.


    Thanks for your time!

    [/ QUOTE ]

    First:
    If it's 76 and auto it has the 203.

    Do you have a chrome flat dome cover at the end of your axles? if so then you have the slugs or in other terms an all the time locked hub.
    This setup is full time all wheel drive and has the ability to lock the center diff in the transfercase to make it like any other 4wd vehicle that is shifted into 4wd.
    Yes these truck did have the option of traction aids, and the most common in those years was the eaton Limited slip.
    The front if there was a limited slip it was a rare option.
    You can tell easily if you lift the truck and turn one side the other would turn in the same direction if it has a limited slip, and in the oposite direction if it is open or has the Gov loc, which I doubt is in this truck.
     
  3. big d

    big d 1/2 ton status

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    it should be an np203. if ya got lock outs, them someone has done some converting to part time, cuz they originaly didnt come that way. it will be reliable to have rebuilt, but the np205 is generaly considered the best. as for the locking devices, im not sure about. ya could pop the covers and check em out or check out the rpo tag in yur glove box.good luck. /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif
     
  4. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    yep the np203 is full time.

    the front hubs are locked all the time, you can't unlock them with out getting a conversion kit to convert the tcase to part time.

    the full time works exactly like the open diff in a rear end. it has spider gears and when the front looses traction, all the power goes to the front.

    there was a "posi" option for the rear, its the gov lov, its an actual locker, its a pile of crap, they blow up after a while. AFAIK there was no factory option for a front "posi"

    i would convert it to part time, everything is spinning in the front, it wears conponents out faster, plus it sucks the milage away, as the motor has to spin all that stuff also.
     
  5. bga

    bga Registered Member

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    Ok, thanks for the answers.

    On the PosiTrac situation, here is what I have tested and found:

    Normally on an Open Diff, you spin one tire and the other spins opposite, or you can hold the other tire from spinning at all. When I try this on this truck, the wheels do spin opposite but it is not possible to hold the other tire from spinning. This has lead me to believe it has some sort of posi unit, however I may be wrong. I'll know for sure this weekend when I bust the covers off.
     
  6. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    Ok, thanks for the answers.

    On the PosiTrac situation, here is what I have tested and found:

    Normally on an Open Diff, you spin one tire and the other spins opposite, or you can hold the other tire from spinning at all. When I try this on this truck, the wheels do spin opposite but it is not possible to hold the other tire from spinning. This has lead me to believe it has some sort of posi unit, however I may be wrong. I'll know for sure this weekend when I bust the covers off.

    [/ QUOTE ]

    Well the other tire spins opposite so you have open diffs.
    The reason you can't stop the other side from spinning is that you have it in gear.
    Put it in neutral and you can spin one side without the other because the driveshaft now can spin.
    /forums/images/graemlins/thumb.gif
     

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