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my 12bolt is better than your 14

Discussion in 'The Garage' started by fasthumpman, Mar 20, 2006.

  1. fasthumpman

    fasthumpman Registered Member

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    eh jk bout that. from what ive searched i should bow down to the all might 14 bolt . but i do have a question though. can anyone identify this axle. its a 12 bolt but is there anything special bout it? its from a 1980. but both rear tires spin in the mud. does that mean its a "gov lok"??? are those bad?? what are those! ive searched the forums havnt really found what im lookin for. my thanks to anyone who replies to my noobie question. [​IMG]
     
  2. MattK

    MattK 1/2 ton status

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    nothin real special about the 12 bolt. its another halfton axle that demands replacing! lol. yeah both of em spinning probably means its a govlock. some 12 bolts also had an eaton clutch type limited slip, but i dont think they came in models as "recent" as 1980. if its a govlock, they are known to be more or less a timebomb. as cheap as 14 bolts are(relative to other mods in this hobby:eek1:) it generally isn't smart to dump much money into a halfton rear axle.
     
  3. goldwing2000

    goldwing2000 Guest

    :thinking: Honestly, I've never heard of or seen a gov-lock 12-bolt. Not saying that they don't exist, just that they can't be very common. It's probably some sort of limited slip/posi unit or (if you're very lucky), somebody dropped a locker in it sometime in the past 26 years.
     
  4. wildmouse216

    wildmouse216 1/2 ton status

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    My K5 is an 80 also and it has the original sticker in the glovebox and it has the tow package and the "locking differential" is part of the tow package. I have put nearly 275,000 miles on my truck and have been through two engines, two transmissions, two transfer cases, replaced both driveshafts, broken hubs, broken front axles, Broken shocks, broken shock mounts, broken at least one leaf on all four spring packs, dented every body panel imaginable, and still have never had a problem with the rear axle. It still spins both 35s in the mud with stock gears no less. I say poo on saying Guv bomb.:eek1: It is as good a locker as any if you take care of it. You should lose the big lift blocks though.
     
  5. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    I saw two dozen or so when I went looking for my open 12 bolt a couple years back ................nearly every one exploded :thumb:

    Open is where its at with 12 bolts ............. open with a Lockright , I have 2 and no one can pay me enough to run a 14 bolt rock grabber :D
     
  6. Masiony

    Masiony 1/2 ton status

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    is every one forgetting that even open diffs can spin both the tires if the traction is more or less equal? slippery mud can cause both tires to have the same amount(or lack there of) traction. and limited slips flat out suck in any high traction situation. they fail when you need them most. mud may be one thing, but rocks are a whole different animal. and i would say that a 12 bolt is ok up to a 36" tire or so. i wouldnt push it past that, especially if it wasnt open. you dont want to break an axle and have your tire go rollin down the road.
     
  7. blazinzuk

    blazinzuk Buzzbox voodoo Premium Member GMOTM Winner

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    Couldn't of said it better my self. you could be totally open and if traction is equal side to side you will spin both tires all the time.
     
  8. Masiony

    Masiony 1/2 ton status

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    heres a way to tell what it has with out taking the cover off. jack up one tire. then try and drive off the jack. an open diff will just spin the tire that is in the air. a limited slip will try and get off the jack but probably wont. a full locker will walk off like the jack wasnt there.
     
  9. pvfjr

    pvfjr 1/2 ton status

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    You're going to confuse everyone with your inconsistent screen names, newbie.
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    A gov-lock will somewhat act like a locker though too, may spin the tire up in the air for a second, but it should (as with all gov-locks, "should") lock the other axle and move the other tire.

    Service manual test for gov-lock proper operation is here, jpgs 4-5. Sorry dial-up folks:

    http://dyeager535.topcities.com/posipictures.html Even GM states "if operating correctly" lol.

    I don't know that I'd like the "surprise" of having a gov-lock operate correctly with just one wheel in the air. :)
     
    Last edited: Mar 21, 2006
  11. lamberthkp

    lamberthkp SITFU Premium Member

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    i never have had much luck out of the ol 12bolt im as bad on them things as trannys i think i have been through 3 so far . i had one of them beefed up i be dang if i ever wast money on one of them things or any 1/2 ton rear end . i threw a 10bolt back under mine last year after i tore up all my extra rear ends . just got me a 14sf but havent gotton to put it under the blazer yet.
     
  12. fasthumpman

    fasthumpman Registered Member

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    sounds like im just gana tear that 12 bolt up till it explodes. yeh the blocks are commin off soon but im still all confused on shackle flips and all that. thanks for all yall's posts. oh and one more question. and this is a newbie question. if my rear end goes bad can i still make it home??? disconnect the rear and drive home with the front tires?? im new to off roading so i dont know what it means to "blow" your rear end. i get the concept that you F*ck it up but im lost in newbie land.
     
  13. Leper

    Leper 1/2 ton status

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    Depends on what goes wrong. Usually you cannot drive it anymore. Even with the driveshaftremoved, the internals will still turn(if they can).

    Don't ever put power to a driveline while on a single jack.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    Since the axles on the 10/12/14SF are all retained by c-clips, *typically* when they come apart something that helps retain the c-clips is affected, meaning eventually the c-clip will fall off, or the carrier bearings fall apart, etc., resulting in the axle sliding out of the housing. (or breaking)

    If all you did was break the teeth off of the ring or pinion, or destroy the side or pinion gears, yes you could drive in 4wd, again as long as something in the rear (large metal pieces) wasn't leading towards catastrophic failure.
     
  15. goldwing2000

    goldwing2000 Guest

    The only blown-up 12-bolt that I've seen personally had the head broken right off the pinion and jammed in between the carrier and the housing. That baby wasn't moving ANYwhere. :D
     
  16. R77K10

    R77K10 Banned

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    i see 12 bolts break when the pinion nut comes loose, and it happens often..,

    the only other thing crappy about the 12 bolt is the smaller pinion stem diameter, 12 bolts have the smallest one, truck 12 bolts that is, not the car ones, the car ones are bigger


    gov lok is governed to kick in starting at 100 RPm difference from one axle to the other

    on an open diff the tire with least traction will spin

    with posi its the axle with the most traction that will get the power

    some opens will act like a locker such as when your burning out on gravel, etc,

    now and then

    good luck
     
  17. 87BrnRsd

    87BrnRsd 1/2 ton status

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    In our hobby, its not gonna be taken care of well. All you can really do is keep the fluid fresh and full, but its still gonna take a pounding with 35+" tires. And I would argue that gov bombs are probably one of the worst lockers out there. Sure they work, but they have a big problem. A lot of times, gov locks will let one tire spin really really fast before locking the other one up. Then, when it locks the other one, too much rotating motion, and kaboom, it blows itself up. My detroit on the other hand locks almost instantly. I have never let someone else drive my truck while I watched, but from driving it myself it feels like the rear will lock in low traction situations with only about 1/2 a tire turn. In any case it wont let one spin like hell before locking them together like a gov lock will.
    -Harrison
     
  18. Masiony

    Masiony 1/2 ton status

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    a gov lok, posi, and limited slips are all the same thing. they still has clutches that try and equal the torque to both wheels. they just have a few design differences. and limited slips will NOT give power to the wheel with the most traction. if you have a tire up in the air, that tire will get most if not all the power. a limited slip tries to take some of that power and give it to the tire with the traction. and all limited slips (other than the true-trac style) wear out continually and never get better from the day they are installed. buying a limited slip is like spending money on a IFS lift. they both work good for the mall parking lot.

    are you serious? are you worried about something that occurs when wheeling anyways? if you take a little precaution you will be fine. just dont something stupid like be under there or have something in front of you. but there is nothing wrong with putting power to your wheels with one or anytires off the ground. just dont be an idiot and you will be fine.

    i signed up for this site a long time before all the other ones. thats why i have this name on here.
     

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