GMT 400 front end rebuild + lift kit

Discussion in 'Full Custom Suspension / Cages / Fab' started by noabarron3, Jul 27, 2020.

  1. HotWheelsBurban

    HotWheelsBurban Burbs are great!

    Messages:
    841
    Likes Received:
    487
    Joined:
    Sep 18, 2019
    Location:
    Stafford, Texas
    Nice projects, both of y'all! I like the 2 door Blazer/Tahoe, but never have had one. Big daddy Burb for me,and this is Burb #7 in my family. None 4x4, but my dad's 06 Denali is awd. Haven't done more than hubs and brake pads on it. Done more front end work on the C1500 Suburban, but it's 2wd so lots different than the K series. Did all the work on mine with it on jackstands or sitting on the floor jack for the brake pad replacement. One side at a time, not too bad.
     
    SUBURBAN5 likes this.
  2. bigredbikerMike

    bigredbikerMike Newbie

    Messages:
    3
    Likes Received:
    4
    Joined:
    Thursday
    Location:
    East Alabama
    There is very little rust under this truck. We wash, degrease, prime and apply truck bed liner to the frame as we go along plus clean, prime and paint small parts. As we have progressed through the project our attention to detail has improved. Recently we went back and disassembled some earlier steps to apply paint. In the rear end photo you can see where the axle saddles have been painted blue and the rear diff cover has a fresh coat of black. We are trying to stay with the black and blue accents.

    The job is very doable using only jack stands. The pictures involving the front end were taken this week. This is the current state of build on this truck and if you look closely you can see the stock torsion bar adjustors laying under the middle of the truck.

    This weekend we will be tearing down the 3/4 ton front end, reassembling the case and trying to figure out what will be required to install it into the truck. My biggest concern is the length of the CV axles and the width of the diff assembly. The 3/4 ton diff is about 1 and 1/2 inches wider than the 1/2 ton diff.

    Front Diffs.jpg

    Our lift kit came with add-a-leafs for the rear, one leaf per side. It added quite a bit to the height of the truck. You can see in the side shot of the truck with the front jacked up high enough to remove the tires and allow room for work the front is just higher than the now normal ride height of the back. You will need to get new U bolts for the rear axle! Be aware of this before you get started.

    Since we changed the rear carrier to the Auburn ECTED and changed gear ratios, I decided to remove the axle from the truck. This made setting up the pinion depth and backlash much easier than doing it under the truck. The biggest trouble here was getting the brake lines disconnected. Twenty five years of road grime had covered and eroded so much that it was difficult to tell how to disassemble the e-brake lines. You will probably need a new brake line once the rear lift is in.

    44757.jpg

    This is a fun project for us as well. My son got hit and rolled my 88 Sportside so this will be his transportation vehicle. Once the suspension and steering is done we will have to rebuild the transmission because 3 and 4 are going out on it.
     
    Last edited: Jul 31, 2020 at 1:31 PM
  3. noabarron3

    noabarron3 Newbie

    Messages:
    6
    Likes Received:
    3
    Joined:
    May 22, 2020
    Location:
    Texas
    Hate to see that on your 88. A lot of good advice. My transmission downshifts are a little rocky, instead of rebuilding I plan on nv4500 swapping. Why kind of miles have you got on yours?
     
  4. bigredbikerMike

    bigredbikerMike Newbie

    Messages:
    3
    Likes Received:
    4
    Joined:
    Thursday
    Location:
    East Alabama
    I have about 300k on the truck and about 15k on this trans. We don't have any good shops around here so if it gets rebuilt again I will have to do it.

    I really like the idea about switching to the NV4500. I'll keep that open as an option instead of of rebuilding the 4L60E.

    We replaced the stearing gear box this weekend. Its not too bad of a job when the whole rest of the front end is apart!
     
    HotWheelsBurban likes this.

Share This Page