rearend swp

[mystur]

Hello all,, have a question  i have a 1980 gmc sierra classic 1/2 ton pickup auto,,i also have a complete rearend assembly from a 1990 silverado step side truck with 3.42 posi gears,wanting to know if this rearend will bolt into my 1980 gmc,,and info online to specific widths ,possible mountings or swap overs ,thanks again,,,,

[fitz]

It's not a bolt in deal.
GM made millions of 73-87"s,  it should be easy to find one that will bolt right in.

[Blazin]

X2 on what fitz said.

[Stewart G Griffin]

https://colemans.com/shop/military-vehicles/rear-axle-assembly-chevy-gmc-u-s-g-i/

[roundhouse]

The distance between the springs is different




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[Edemich]

What type of rear end? 12 bolt, 14 bolt, semi float, full float

The spring width is different, shock mounting tabs won't match and your parking brake cable will have to be figured out.

It is doable.   It will require welding! I put a 14 bolt full float rear end out of a 2001 Silverado 3/4 ton in my 85 truck.   It has 4.56 gears and is going to look awesome from behind in between my 35" tires.  I got Spring perches from ruff stuff specialties.  Plasma torched the old ones off, welded new ones on, moved my brake line from passenger side to driver side and got the drum in hat parking brake hooked up and the best part is no need for disc brake kit as it already has them.  The axle is wider but I have always thought our trucks look a little skinny form behind because the tires sit too far in the wheel wells.

If you are patient though you can find one from our year trucks except it won't have disc brakes.