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12 bolt vs. 10 bolt....benefits??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BLzr4x4ngkid, Jun 18, 2000.

  1. BLzr4x4ngkid

    BLzr4x4ngkid 1/2 ton status

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    My friend told me last night that he would sell me his spare 12 bolt for $20. It needs a new carrier and spider gears, but this seems like a good opportunity. I know the 12 bolt is stouter than the 10, but what would I be benifitting from it?? I'm going to buy it for sure and while it's not under my Jimmy, I'll have a locker and 4.10 gears put in it. Thanks

    Alex
    [​IMG]What me get stuck? NEVER!![​IMG]
     
  2. Jason73K5

    Jason73K5 1/2 ton status

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    The 12 bolt is only marginally stronger than a 10 bolt and is probably not worth the swap unless you are having problems with your current axle. The 14 bolt would be a much better upgrade if you're going to swap, just keep your eye out for good deals.
     
  3. bablazer73

    bablazer73 1/2 ton status

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    I like the 10 bolt axels. I have been told I am a moron, idiot, dumbazz, and other choice names, but I have had better luck running 10 bolts over 12 bolts. upgrade parts are all over the place for these axels. every camaro/ta had them from 70-81. posi's all over. lockers, gears, whatever you need. ran one for years in a 11.0 second, nitrous feed smallblock camaro. if your not having a problem with the axel now, why switch. If you are having problems, is it normal wear and tear? if yor running larger than 35's, or serious off road pounding I would reccomend the 14 bolt full floater. if ground clearance is a concern, maybe just a full floater kit for your 10 bolt, and a good carrier is all you need.

    your right. I don't understand the jeep thing!
     
  4. Black89k5

    Black89k5 Registered Member

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    You think you've been called names. I had a 78 pickup and had 10 bolts. This damn thing was lifted 10 inches with 40's. I went through 3 rears and about a half dozen driveshafts in one summer of blood, sweat, tears, and a lot of beer. I blew a driveshaft out one day and ran it around in 4-wheel drive for a week till i could find another.
     
  5. 87Blzr

    87Blzr 1/2 ton status

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    The biggest thing I hate about the swap is the tiny winy u-joint used with the 12 bolt. That u-joint always goes long before the front joint on the rear driveshaft even though the front joint is at a much steeper angle. I must upgrade the rear yoke and recommend the same if you do the swap

    87 K5 Siverado, 68 SS 396 Camaro
     
  6. 6.2Blazer

    6.2Blazer 1/2 ton status

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    The 12-bolt is a little beefier than the 10-bolt. I would say if you have a stock 10-bolt now, and want to change to lower gears and maybe a locker, then go ahead and build the 12. It should also work out well since you could do all of the work on the 12 with it out of the truck and not have the truck down when you are doing it.
    The 12-bolt has an 8 7/8" ring gear vs. the 10's 8.5", and all 12's have 1.31", 30 spline axles vs. the 10-bolts 28 spline, 1.28" axles (except for some later models which had the 30 spline axles).
     
  7. Boss

    Boss 1/2 ton status Author

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    Build the 12, you'll be much happier in the long run. I wouldn't say the 12 is a little bit stronger than the 10, I would say it is much stronger. I have a 12 on my K5 with 35's and do some tough wheelin every now and then and no probs yet (knock on wood). And like 6.2 Blazer said, build up the 12 while its off the truck. Good luck
    Boss
     
  8. Steve_87K5

    Steve_87K5 1/2 ton status

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    speaking of 10 bolts, I saw a 1350-series drive yoke for a 10 bolt in a magazine article. Does anyone know the part number and manufacturer?? I have had NO problems with my 10 bolt front end w/home made truss. I like Dana 60s but I'm gonna keep my 10 bolt up front for now...steve '87 K5

    SteveB
     
  9. BigBadBowTie

    BigBadBowTie 1/2 ton status

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    Puny U-Joint solution

    Ok, I know everybody's been wanting this information. I recently uncovered my receipt & here are the part numbers.

    National Seals #3896
    1350 U Joint
    10 Bolt Yoke

    These parts will allow you to run the larger 1350 U-Joint on a 12 Bolt axle. The yoke is available from GM, & http://www.sixstates.com as well as other places I'm sure. The Seal & U-Joint should be available at your local part store.

    This set up allows you to run a 10 Bolt yoke on a 12 Bolt rearend. I've been running this setup for 2 years now. If I remember right there's a small piece that needs to be removed from the seal in order for this to work, it will be obvious when you see it & it's easy to remove. (NO LEAKS)



    Rick
    86 K-5
    http://www.BigBadBowTie.ColoradoK5.com
     

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