Rear Axle Swapping truck to van...

Discussion in 'GM Powertrain' started by bluebellbus, Sep 30, 2011.

  1. bluebellbus

    bluebellbus New Member

    I have a 1990 G30 van with a bad semi floating 14 bolt and I'm wondering whether I could use a 1 ton single wheel truck with a full floating axle as a donor for a new rear end? Are the widths interchangable or am I going to have to find another van as a donor?

    Thanks for your help in advance
  2. Crawdaddy

    Crawdaddy has no brakes Staff Member 5+ Years 1000 Posts Platinum Contributor

    According to the 14-bolt bible (Pirate4x4.Com - Extreme Four Wheel Drive), no, they will not interchange. The Pickup has a width of 67.5" where you van is 70" wide

    TypeWidth WMS-WMSTube OD / ThicknessApplicationsHubs* Shafts**

    (single rear wheel truck)
    67.5" 3-3/8" / 0.5"Type A Type 1

    (dual rear wheel truck)
    72"3.5" / 0.5"Type B Type 2

    (cab and chasis truck)
    63.5"3.5" / 0.5"Type B Type 1

    70"G30 and G35Type A Type 3

    A truck rearend will be too narrow. Unfortunately, I think this is one of the rare cases where you need to find one out of another van or rebuild yours. You are correct that typically they're interchangeable, but the G30 vans appear to be different. Measure it out with a tape measure to be sure.
  3. bluebellbus

    bluebellbus New Member

    Thanks for the quick reply. Lots of good information there. Excuse my lack of understanding, but what does the 70" width refer to? Axle to Axle including hub and drum? Or is it just the width from each inside of the drum where it mounts?
  4. Crawdaddy

    Crawdaddy has no brakes Staff Member 5+ Years 1000 Posts Platinum Contributor

    Axle widths are typically expressed in wheel mounting surface to wheel mounting surface. That should mean that if your drum slides onto the hub, then the drum's included.
  5. bluebellbus

    bluebellbus New Member

    Ahh, I understand. Well I just came across a 2002 14 bolt with a 3.81 ratio. It doesn't say much about years. Would anyone happen to know if that would fit??
  6. bluebellbus

    bluebellbus New Member

    Anybody? I can get one from a guy for an absolute steal?
  7. bluebellbus

    bluebellbus New Member

    2002 GMC 1 ton van rear axle swap into 1990 GMC G30 van???

    Hi All,

    Can someone with rear axle expertise tell me if I can swap this into my van? I have a 1990 GMC G30 with a 14 bolt 3.73 axle. It has bad bearings or more and needs to be replaced. I have available to me an axle out of a 2002 1 ton GMC savanna with only 100K. So my question is, is this axle swappable? Or are they completely different? It's 14 bolt like mine so the owner says, and it also has a 70 inch width drum to drum, like mine.

    I'd appreciate any help anyone can offer. Thanks.
  8. Crawdaddy

    Crawdaddy has no brakes Staff Member 5+ Years 1000 Posts Platinum Contributor

    Similar threads merged.

    If the WMS widths are the same, spring perch distance the same, and shock mounts the same, you're good to go. Measure the axle for yourself, don't take the word of the guy since these axle variations look so similar.

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