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6 lug 4x4 suburban to 3/4 4x4 lwb truck frame swap. “Squarebody”

Discussion in 'Suspension, Steering & Brakes' started by buddy350, Mar 25, 2020.

  1. buddy350

    buddy350 Full Access Member

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    Here we go

    I’ve looked and cannot seem to get a concrete answer.

    1986 4x4 suburban with 6 lug axles.

    Donor truck 1984 3/4 ton 4wd with bbc and manual transmission.

    ive got everything to get the ball rolling but discovered the frame on the burban looks thinner than the 3/4 ton donor truck.

    ive tried contacting Diy4x to see about getting the boxes frame kit.

    have not yet heard back from them.

    worst case I was considering putting the suburban body onto the 3/4 ton frame.
    ive read that the lwb donor frame will be about 5 inches shorter at the rear.
    I can work with that.

    question
    Will the 8 lug axles simply bolt into the suburban frame?

    If I cannot find a solution to strengthen the suburban frame is it possible to put the suburban onto the 3/4 ton frame?


    btw
    I’ve already pulled the motors and transmissions on both the suburban and the donor truck and have already pulled the axles on the donor truck.

    I appreciate any feedback.

    stan in Dallas,Tx

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  2. Arkansas_V8

    Arkansas_V8 Proud Redneck

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    Yes they will bolt in. U-Joints are bigger on the 3/4 ton. But you may be able to swap in the shafts. Not big enough frame difference to justify the body swap unless you just want to.
     
  3. TubeTruck

    TubeTruck I like anything fast enough to do something stupid

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    Yup, Axles will bolt right in just use the drive shaft out of the 3/4 ton, they should be close in size, or get a combo joint or new drive shaft. Keep the Suburban on the Suburban frame. The Suburban frame drops down in the rear while the Pickup is straight. I figured this out when hunting for a hitch. Plus the body mounts are in different places and different heights. Not worth the trouble imo unless the Suburban frame has holes in it.
     
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  4. Craig 85

    Craig 85 Full Access Member

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    The wheel base is different. The Suburban is shorter. I've done 3/4 axle swaps in both of the below trucks (1/2 tons). Pretty straight forward. You need the rear spring plates from the 3/4 ton and make sure to use a 3/4 ton master cylinder. The hybrid U-joint I used at the rear axle Spicer 1310-1350 Part# 5-460X or O’Reilly’s – Precision U-joint Part# 348 (3.219 / 1.062 to 3.625 / 1.188)

    The bottom truck was already lifted, so no change to the front axle. Due to the fact I used a 14 bolt SF, I had to shorten the rear drive shaft. It looks like your truck has one too. I don't see the hubs sticking out.

    ORD build up a Suburban a few years ago. Here's the link.

    http://ww.offroaddesign.com/action/burly-burb.htm


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  5. RoryH19

    RoryH19 Full Access Member

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    How wide are your tires on the K5? Were they flush with the fender flares?
    I was thinking of adding the Xenon ones to mine. No cutting required. Running 33x12.5 MT
     
  6. buddy350

    buddy350 Full Access Member

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    I really appreciate the help.

    I’ve actually got another manual shift 3/4 donor truck as well.

    As soon as I get the suburban going I’ll be selling both of the 3/4 ton manual shift donor trucks.

    I bought the second donor truck because it already has a lift kit and a fresh rebuilt manual transmission.
    Plus has some serious custom front and rear bumpers.

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  7. Craig 85

    Craig 85 Full Access Member

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    The K5 had 15/36R16.5 Cepek Fun Country II's with 9.75" wide wheels. BS on those were 4.75". The fronts were close to flush with the flares, but the rear were an inch or more under the flare. I don't have a rear have a rear picture with the flares and those wheels, but here is one before the flares and bigger rubber. They were 12/16.5 bias plys on 8.25" wide wheels.

    On my K30 I have 305/70R16's (32.8" x 12") with a 16x10 wheel (4.5" BS). You can see the rear is under the stock wheel well.

    1977 K5 rear.jpg
    IMG_2452.JPG
     
  8. Craig 85

    Craig 85 Full Access Member

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    Nice, Dana 44 large hub.
     
  9. RecklessWOT

    RecklessWOT Full Access Member

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    Man, it must be nice living places that trucks don't rust to shit. I would be estatic to find one of those trucks, let alone two. Around here those "donor trucks" would be sold as "super clean" and would probably go for 3 grand each. ESPECIALLY that round eye. Hell, I'd daily the thing just like that
     
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  10. bucket

    bucket Super Moderator Staff Member

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    That #348 u-joint, was that for use with a 12-bolt rear axle? I needed a #447 when I swapped out my 10-bolt to a 14ff.
     
  11. Turbo4whl

    Turbo4whl Full Access Member

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    My feedback, 'I spy a rat, NICE!'
     
  12. RoryH19

    RoryH19 Full Access Member

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    Ok thanks. 15" wide tires works well with those flares. I'm staying with 12.5 so not sure how that would look. May just have to buy and see. Can always return.
    I have a 14bSF 6 lug from a gmt400 which is ~the same width as the front so it would match.
     
  13. buddy350

    buddy350 Full Access Member

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    WOW Thanks

    I have no idea what a Dana large hub is or even means.
    Dont know a whole lot about this kind of stuff.
     
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  14. buddy350

    buddy350 Full Access Member

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    Thanks but its not as wonderful as one might think, That second donor truck has serious rust issues even for us Texans. The bed is rusted and the rockers are rusted pretty good.
    The 1st donor truck is rusted pretty good as well especially on the firewall.
     
  15. TubeTruck

    TubeTruck I like anything fast enough to do something stupid

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    Rust is fine, rot is what you don't want. @RecklessWOT is talking about stuff like this. This is what we get in the rust belt lol

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