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3/4 vs 1 ton axles?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by meatloafK5, Oct 24, 2002.

  1. meatloafK5

    meatloafK5 Registered Member

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    I have a question regarding a 12 bolt complete axle vs the 14 bolt. Do the 12 bolts from lets say a 3/4 ton Suburban have the same spring perches as a 1/2 ton Blazer? If so, then I assume its a direct drop in except for the 8 lug wheels and the brake lines right? honestly I don't really need a 1 ton set up. I am not plannin to go with anything bigger than 35" tires.
    I am just trying to go with the easiest mod vs having to weld for a 1 ton rear end or even front.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  2. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    3/4 tons didn't have 12 bolt rears, they had 14 bolts, either a full floater or semi-floater depending on the year. But yes, the spring pearches are in the same location on a 3/4 ton and 1/2 ton.




    Mike
     
  3. Muddytazz

    Muddytazz 1 ton status

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    The spring perches were different with the 1ton 14bff.
     
  4. meatloafK5

    meatloafK5 Registered Member

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    My bad! I had 12 bolt on the mind for some reason, thanks for clearing that up. Thats what I was looking for. Now how about the 3/4 ton pickups like the 2500 Silverados? Would that still be the same as a 3/4 ton Suburban?
    Thanks.

    /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif
     
  5. imiceman44

    imiceman44 1 ton status

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    Never say never, 3/4 ton trucks did come with 12 bolts or 14bSF.
    3/4 ton vans Came with either 12 bolts or after 79 10bolt 30 spline.
     
  6. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> So that would be the rare 8 lug 12 bolt? Did those have 12 bolts in the front too? /forums/images/graemlins/smirk.gif </font color>
     
  7. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    You might want to go back and check your facts! NO GM 3/4 ton truck ever came with a corprate 12 bolt rearend.


    Mike
     
  8. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    Any 3/4 ton 14 bolt(sf or ff) will bolt up under your blazer withoug spring pearch or shock mount modification.


    Mike
     
  9. jackedjimmy350

    jackedjimmy350 1/2 ton status

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    /forums/images/graemlins/rolleyes.gifdidnt someone on here claim to have the famous 12 bolt front? /forums/images/graemlins/ears.gif
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Yeas...that was executioner way back when. Eventually someone got a good clear pic of his front end...D44/forums/images/graemlins/rolleyes.gif

    He was just having some fun though...

    Rene
     
  11. imiceman44

    imiceman44 1 ton status

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    Actually they came in 2wd trucks only, and they were 1/2" 5 lugs.
    Don't make fun, GM did a lot of weird things in transitionning so never say NO.
    By the way, about 12 bolt fronts, I have seen an article about the new 1 tons, and they are supposed to be coming with 12bolt fronts only IFS. Too bad, that would have been nice to have. /forums/images/graemlins/frown.gif
    I have seen 14bolt fronts before but same as the 9" fronts, those were custom made. /forums/images/graemlins/smile.gif
     
  12. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    I say again, GM NEVER put a 12 bolt in a 3/4 ton truck.


    There is no such thing as an 8 lug 12 bolt. The light duty 3/4 tons that came out in '88 had 14SF rears with 6 lugs.


    Mike
     
  13. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> Hmmm, I think a 5 lug 12 bolt in a 3/4 ton sounds about as likely as an 8 lug 12 bolt. If you have pics, I'd love to see them, if not, then I'll reserve my final decision until I see one. That being said, I think you're the only one in here to have ever seen a 12 bolt in a 3/4 ton. If it had 5 lugs, I think that would make it a 1/2 ton. Maybe the truck had the wrong badges on it or something, that seems a lot more likely.</font color>
     
  14. imiceman44

    imiceman44 1 ton status

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    Well go out and check any 20 series or 2500 series, 2wd and tell me what you find. Those to the best of my knowledge, are the 3/4 ton right?
    Remember one thing though, in GM as well as ford and Dodge, 3/4 tons came in 2 configurations Light duty, and Heavy duty.
    The light duty came with 12 or 10bolts yes 10 bolts, with five lugs 1/2" lugs.
    The HD came with 8 lug 14 bolt SF only 4wd models came with the six lugs.
     
  15. imiceman44

    imiceman44 1 ton status

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    About the 12 bolt 8 lug, I have yet to see one.
    I don't think they exist.
    But again I say, I think, because I don't like to be the smart alec that will confirm that if I never saw it , that means it doesn't exist.
     
  16. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> All of the 3/4 tons that I've seen have either a 14bSF or a 14bFF, all of them 8 lug. I've seen 14bSF in 5 and 8 lug, but never seen a 10 or 12 bolt rear in the back of a 3/4 ton. Not trying to be a smart alec, and I didn't say that there's no way that they existed. GM did do some strange things, but 1/2 ton axles in a 3/4 ton seems a bit far fetched to me.

    *EDIT* I think the confusion here is that iceman went off on a tangent from trucks and started talking about vans. I'll be the first to admit that I don't know much about GM vans, so I will bow out of this discussion until it turns back to trucks... /forums/images/graemlins/thumb.gif</font color>
     
  17. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    GM never produced a 5 lug 3/4 ton! 3/4 ton trucks all came with 8 lugs until the new body style in '88 when they introduced the light duty 3/4 ton that had 6 lugs and a 14SF rear. GM has done some crazy things but they have never put a 12 bolt or a 10 bolt in a 3/4 ton truck whether they were 2 or 4 wheel drive. When you find that elusive 5 lug 3/4 ton make sure and send me some pictures of it! /forums/images/graemlins/rotfl.gif


    Mike
     
  18. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    Wes, where are you? Step in here and help me set Iceman straight. He obviously isn't going to believe me. /forums/images/graemlins/grin.gif



    Mike
     
  19. Waxer

    Waxer 1/2 ton status Author

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    Mike,

    I've done quite a bit of research on this and found the following.


    1/2-ton pickups (10/1500-Series)

    1964-82
    GM 12-bolt 8.875-in. GM 12-bolt 8.875-in.

    1983-87
    GM 10-bolt 8.5-in. (SF) GM 10-bolt 8.5-in. (SF)

    1988-Present
    GM 10-bolt 8.5-in. (SF) GM (ICA)


    --------------------------------------------------------------------------------



    3/4-ton pickups (20/2500-Series)

    1964-82
    GM 12/14-bolt 8.875-in./9.5-in. GM 12 bolt 8.875-in. (FF)

    1983-87
    GM 10/14 bolt 8.5-in./9.5-in. GM 10-bolt 8.5-in.

    1988-present
    GM 14-bolt 9.5-in./10.5-in. (SF/FF) GM (ICA)


    Now this was off the following site
    http://www.biram.com/offroad/techspec/axleguide.html

    I also found another site that described numerous axles and the applications for each.. Which states...

    &lt;snip&gt;
    GM CORPORATE 12-BOLT
    The stronger 12-bolt, with an 8 7/8-inch-diameter ring gear, can be found in various 1964-82 GM 1/2- and 3/4-ton
    front- and rearends.
    &lt;/snip&gt;

    I've found many more which say the same thing. I have not checked my FSM tho on the issue.
     
  20. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    &lt;snip&gt;
    GM CORPORATE 12-BOLT
    The stronger 12-bolt, with an 8 7/8-inch-diameter ring gear, can be found in various 1964-82 GM 1/2- and 3/4-ton
    front- and rearends.
    &lt;/snip&gt;


    [/ QUOTE ]

    I will throw this out due to the 12 bolt frontend comment! /forums/images/graemlins/rotfl.gif

    When you find one of the 12 bolt full floating rear ends(that wasn't converted with aftermarket parts) I want to see it! I have a stock '78 3/4 ton 4x4 out back right now that has a 14 bolt 10.5 inch ring gear full floating axle in it. Your source doesn't even mention this rear for this application. Which by the way was the only rear that came in a '78 3/4 ton truck. I don't know where this person got their "facts" but they are WRONG! I have been dealing with Chevy trucks for a lot of years and I have NEVER once seen a 3/4 ton with a 1/2 rear from the factory.


    Mike
     

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