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Obvious Newbie Question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by PerdidoK5, Sep 4, 2002.

  1. PerdidoK5

    PerdidoK5 1/2 ton status

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    I have a '79 K5 with auto locking hubs. Why does everyone want to replace thier auto hubs with manual locking hubs? Do the auto hubs fail?
     
  2. beater74

    beater74 1/2 ton status

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    they suck, /forums/images/icons/shocked.gif they will lock when you don't want them to and not lock when you need them to. i've heard of one of them failing and locking up sporadically and causeing serious handling issues on the road. and they cost twice as much to replace. /forums/images/icons/grin.gif
     
  3. Panther

    Panther 1/2 ton status

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    Do a search on "manual hub". Personally I highly recommend them. You're never really sure about the auto hubs.
    The install's an easy job too.
     
  4. Calclips

    Calclips 1/2 ton status

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    You can feel manual hubs lock in, kinda gives you peace of mind knowing 100% if the hubs are locked or not. Also, somebody correct me if I'm wrong, auto hubs unlock when you go in reverse.
     
  5. shane74

    shane74 1/2 ton status

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    AFA I know, they will only unlock when you go in reverse for at least 10 ft. (really irritating!) I still have them in mine and they work OK, but I think one of them hangs up a bit. I can feel it when I turn a tight corner to the left right after "unlocking" them. Time for the part time kit!
     
  6. Blue85

    Blue85 Troll Premium Member

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    No, they don't unlock in reverse unless you disengage the front driveshaft. Only when you switch to 2WD and then back up do they unlock. You have 4WD in both directions.

    They are attached to 3 things: the hub, the axleshaft and the spindle. The spindle never turns. The hub always turns when the truck is moving. When the axleshaft turns, it spins the indside of the auto hub, engaging it, even when the wheel is turning. In reverse, it is the difference of speeds between the axleshaft and the hub that spins it back out. As long as the speeds are the same, it stays engaged.
     
  7. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    One more thing to add to this. Are you sure you have auto hubs? A '79 should have an NP203 (assuming an auto trans). That means it has drive plates, not auto hubs. If you put manual hubs in and don't put the case into "Lock" you won't go anywhere w/ the hubs in "free" due to the center diff. Unless you have converted you 203 to part-time. Make sense??
     
  8. beater74

    beater74 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    A '79 should have an NP203 (assuming an auto trans). That means it has drive plates, not auto hubs.

    [/ QUOTE ]
    good catch Jim your exactly right
     
  9. PerdidoK5

    PerdidoK5 1/2 ton status

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    Okay, so I think this is what ya'll are saying: I should buy a "part time kit" for my transfer case and replace my auto hubs with manuals. Is this right? Is this something I can do? Thanks. /forums/images/icons/wink.gif
     
  10. PerdidoK5

    PerdidoK5 1/2 ton status

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    My post got buried! Who has done the "part-time kit"? How difficult is it? I belive my axles are both locked, will this make a differance? /forums/images/icons/confused.gif
     
  11. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    If your axles are both locked it would be a bitch to turn on the street w/ it still full-time. What makes you think they are locked? Can you hear a ratcheting sound when you turn?
    Weather (I made a funny) you should convert is up to you. I liked my full time case when I lived in OH and it might be nice in some of the tropical rains you get down in FL.
     
  12. PerdidoK5

    PerdidoK5 1/2 ton status

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    Bear,
    I think it's locked because of the noise it makes when I turn. The tires dig (dirt) and chirp (pavement) the entire radius of any turn, sometimes the truck even hops a bit. It only has 33" Trailblazers on it, and I'm pretty sure the rest of the truck is stock. Like I said, I am a newbie. This my first 4x4, even though I'm Thirty-Something. Is that just "natural" behavior for a truck in four wheel lock? If so, I'm in four all the time. /forums/images/icons/confused.gif
     
  13. Timmer_71

    Timmer_71 Registered Member

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    Yes, that is natural behavior for a truck in 4-wheel "lock"
    just put it in regular 4-wheel and it shouldn't do any of that.
     
  14. Timmer_71

    Timmer_71 Registered Member

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    Maby I misunderstood, but if you have a stock '79 you should not have either "auto or manual" hubs, they are just kinda locked in all the time. the only "locking" going on is in your transfer case when you put it into 4-wheel "lock" otherwise you are just in part time 4-wheel drive and you should not have all the jumping and chirping when you turn.
    So, back to the original question, the way I understand it, is that you do not need to replace your hubs, there is really nothing wrong with it the way it is.
    hope this helps.
     
  15. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    If its in "lock" then it is normal, but if it is one of the normal spots HI or LO than it is not normal w/ open diffs. You are in 4WD all the time. The 203 is a full time case.
     
  16. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Ok lets figure out if you have a part time kit. Unlock the hubs. Set the parking brake. make sure the case is in Hi. NOT Hi Lock. With the hubs unlocked if it has a part time kit you should be able to turn the front drive shaft by hand and see the u-joints in the knuckles turn. If you cannot turn the front drive shaft with the hubs unlocked and in Hi then you are still full time and you need to leave the hubs locked. Some moron put locking hubs on the truck without converting to part time.
    If you can turn the front drive shaft then it's converted and everything is fine. For the street you need to be in Hi and hubs unlocked. Everything that you describe will be normal for a truck with a part time kit and the shifter in a LOC posisition.
     
  17. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Grim he doesn't have locking hubs. He cant do that. Reread the first post. That is why I was going under the assumption it was still full-time.
     
  18. trailblazer87

    trailblazer87 1/2 ton status

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    Even if he did have locking hubs he would be able to spin it by hand due to the center diff.
    My buddy's got a 203 in his Power Wagon and if the front d-line is out and he is not in loc, then he won't move. He has not installed the part time kit either.
     
  19. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Uhhh he says he has AUTO locking hubs. That's still not a Drive flange that a 203 would have.
    But yes lets clear up what he's seeing. \
    Is it just a chrome cap on your front or is it a cap with three screws that say Auto in the middle?
    If it's a Chrome cap then you are full time and BigJBear is absolutly correct..
    If it is a cap with three screws that says auto then my trick will work but you might have to get it in HI drive about 10 ft then back up about 10 feet and that should unlock the auto hubs. Then you can check the driveshaft. It will spin about a revolution or two with locking hub and then it may lock up as the hubs engage, might not. Sometimes you have to be rolling to get them locked.
     
  20. PerdidoK5

    PerdidoK5 1/2 ton status

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    Okay guys (and gals),
    I only have the round chrome caps on my hubs, no screws. I can shift from high to low and back in nuetral, but the only change I see (High lock, High; Low lock, Low) is the obvious gear reduction. I never feel any differance in the "chirping/jumping" characteristics. The truck jumps out of Low loudly with a pop, I thought this might be a linkage problem? /forums/images/icons/confused.gif
     

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