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GM axle swaps...How easy are they?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Mudstud, May 29, 2001.

  1. Mudstud

    Mudstud 1/2 ton status

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    I need just a little clarification. Do GM axels ie. rear ends and front ends swap easily into our trucks...1976 K5? Easy as in the spring perches are the same distance apart as ours and the shock mounts are close to ours. I know the U-joints wouldn't match up but that's fixable. I know that GM has at least 2 rear ends with different widths, truck/van. So whats the skinny on this? Can I go buy a corporate 14 out of a truck and replace my 12 bolt (which is clunking and howling)? I know I'd have to upgrade my front to 8 lug. I'm not a welder and can't afford to have somebody cutting and welding on my stuff.

    One last question. My truck has a Dana 44 in front and takes the same U-joints through out and I can't find a part number on the Spicer Dana box the joints comes in or the joint itself. I think I have a 295 joints. Is this right?

    Stuck is a state of mind!

    Mudstud
     
  2. 90K5

    90K5 1/2 ton status

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    If you get a rear end out of a 1/2 ton or 3/4 ton it will bolt up. the 1 tons are different

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  3. thatK30guy

    thatK30guy 1 ton status Premium Member

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    To make a long explaination short, ALL truck, blazer and suburban axles are interchangable, front and rear, any year, EXCEPT, for the 1 ton rearends. The 1 ton rearends have shock mounts and spring perches in the wrong locations as all the other axles.

    When In Doubt, Whip It Out!
     
  4. ut77gmc

    ut77gmc Registered Member

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    I second K30guy....way too easy to swap parts between models. Kind of nice, eh...

    '77 GMC K15 LWB.....likes to get muddy
     
  5. Triaged

    Triaged 1/2 ton status

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    297-x is the one you want it is the one without the grease zerk.

    '71 Blazer CST with alot of rust
     
  6. californiak5

    californiak5 1/2 ton status

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    I just wanted to add a little more to what Wes said.

    The 1 ton (K30) rearends are perfect for the first gen. blazers (K5) as far as spring perches and shock mounts. 1/2 (K10) & 3/4 (K20) ton rearends are perfect for the 73 on up blazers(K5s). All the front ends are interchangeable throughout all year blazers.(I'm talking about all single wheel trucks)

    Or so I have heard.

    See Ya,
    Keith

    [​IMG] <font color=green>Born to Drive My K5</font color=green> [​IMG]
     
  7. TX Mudder

    TX Mudder 1/2 ton status

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    I think the 1972 and older rear axles have the wrong spring perch location for your application. Pick a rear axle from 1973 to 1987 k5, k10, or k20.
    -- Mike
     
  8. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Yep, californiak5 said it. [​IMG] Thanks for reminding me and everybody else about the 67-72 series trucks!!!! [​IMG]



    When In Doubt, Whip It Out!
     
  9. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    So, to clarify, a 14bolt FF, out of a Single Rear Wheel 1 ton will not fit a Blazer?

    I always thought that a SRW 1ton would fit? I am wrong?

    Thanks
    John

    '83 GMC Jimmy 4x4 ZZ4 Crate Motor
    '83 Chevy P/U 4x4 Sand Drag Racer, 578 RWHP
    '94 Impala SS
    '01 Chevy 2500HD w/8.1L & Allison Auto
     
  10. 6.2Blazer

    6.2Blazer 1/2 ton status

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    For most cases that I know of, the 1-ton frames are narrower at the rear, therefore the spring perches are also narrower (closer together) on the rear 1-ton axles. You would have to cut off the spring perches and move them out towards the wheels by about an inch or so....I can't remember the exact measurement now but I do have a 1-ton 14FF in the rear of my '90 K5 and that's how I made it fit. Also, on my axle which came out of a 2WD, the shock mounts had to be cut off and re-welded. They were positioned on the wrong side of the axle tube and too low to work with the stock upper mounts......I don't know if the rear axle out of a 1-ton 4x4 is the same as the 2WD for sure, but I think it is.
     
  11. californiak5

    californiak5 1/2 ton status

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    Hey John,

    It will work as long as you are willing to cut and weld spring perches and shock mounts, or if you have a first gen. blazer.
    If you want a direct bolt in replacement for the 73 on up blazers you would want one out of a 3/4 ton truck.

    See Ya,
    Keith

    [​IMG] <font color=green>Born to Drive My K5</font color=green> [​IMG]
     
  12. Boss

    Boss 1/2 ton status Author

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    Is swapping them easy??
    Pretty much..I did it all by myself!! :)
    Boss

    <A target="_blank" HREF=http://www.boss.coloradok5.com>http://www.boss.coloradok5.com</A>
     
  13. Mudstud

    Mudstud 1/2 ton status

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    Thanks for the insight but what's the highest year I can go for easy bolt on? -I'll want to look for a 3/4 ton rear from a 73 through ???

    ----So I do have 297 joints. Why don't the boxes say that?

    Stuck is a state of mind!

    Mudstud
     
  14. 1big78k5

    1big78k5 Registered Member

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    I would say it's safe to say a rear end from '73 to '87 3/4 ton should fit.

    '78 K5 SB400, T350, NP203, 35" Swampers
     
  15. thatK30guy

    thatK30guy 1 ton status Premium Member

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    If you are wanting to install a 14FF into your rig, then anything between 73 to 84 will work. But keep in mind, during the 81 to 84 years, on the 3/4 tons, the FF's were options, whereas the 73 to 80 years were all standard equipment. These 73-80 FF's are very plentiful. And you can get them for good prices too.

    When In Doubt, Whip It Out!
     
  16. Triaged

    Triaged 1/2 ton status

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    The ??-72 D44 came with smaller u-joints (260???). the 297 came on the 73-. I think they came without the grease zerk too.

    '71 Blazer CST with alot of rust
     
  17. BLzr4x4ngkid

    BLzr4x4ngkid 1/2 ton status

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    I'm getting ready to do a 14FF swap here next week. I'll let you know how it goes. I'll get pics of it too.

    "Don't hit me with them negative waves so early in the morning." Odd Ball--Kelly's Hereos
     

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