10 bolt to 12 bolt swap

I have a 1997 k1500 with a 10 bolt rear with 3.42s and I have a buddy who is building a mud bog truck and getting rid of a 12 bolt rear that has 4.10 gears already. Will that axle fit into my truck without much complications? The 12 bolt is coming out of a square body Chevy not sure on the year

You can make anything fit with a plasma cutter and a welder....lol..

Check the wms(wheel mounting surface) to wms on each axle. That's the main thing. Spring pitches and shock mounts can always be moved with above mentioned tools if need be. But as far as a direct bolt in your gonna have to just start taking measurements where everything is and compare it to the other axle.

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I'm staying tuned because i found a 12 bolt hogs head in a barn that would sure be neat on my 400.

I made a 12 bolt fit in the gmt400 series trucks. I’ll take some pics later tonight, but the spring perch mounts were about 1.5” to 2” narrower than our trucks.

You’ll have to cut off the spring perch and weld new perches or make an offset plate that centers on the old perch and saddles the axle tube.

Brandon Stout said:

I have a 1997 k1500 with a 10 bolt rear with 3.42s and I have a buddy who is building a mud bog truck and getting rid of a 12 bolt rear that has 4.10 gears already. Will that axle fit into my truck without much complications? The 12 bolt is coming out of a square body Chevy not sure on the year

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Hello everyone I am new here and iv been fallowing thus conversation.. And am very interested.. I have some of the same issues.. I have a 97 c1500 two door regular cab with the 10 bolt that just went out and I habe a Doon er truck but it's frok Canada with a 10 bolt amd I am not shur it will work. My buddy told me her as a 12 bolt I can have butt I am wondering if it will be easy to swap or if it's possible any one have any advice on eather rear end and what I should do.. Please need help need to get my truck back up and going so I can get back on the road working..

JLG88 said:

I made a 12 bolt fit in the gmt400 series trucks. I’ll take some pics later tonight, but the spring perch mounts were about 1.5” to 2” narrower than our trucks.

You’ll have to cut off the spring perch and weld new perches or make an offset plate that centers on the old perch and saddles the axle tube.

Click to expand...

flintlock said:

I'm staying tuned because i found a 12 bolt hogs head in a barn that would sure be neat on my 400.

Click to expand...

So woukd it be hard to swap a 10 to 12 bolt because I was given a 12 bolt that's been sitting in a barn aslo and I want to swap it for my 10 because mine just went out and when it went it went bad.. So I need advice badly

My advice? Get a 14 bolt.

What would be different on a Canadian truck that would keep you from using the rear end? It's not like your speedometer is going to magically switch to km. Swap it in and be done.

Many (Many!) of these trucks were built in Canada, then shipped & sold south of the 49th.
The ones sold in Canada had the speedos & odometers in KMs.
IIRC, the early trucks sold in Canada had Big Brother's mandated DRLs before they were standard issue in the states.
...& those are the only differences.
Just because we live in igloos & travel by dog-sled 6 months of the years doesn't mean our trucks are any different than the ones sold south of the border.

Oh yea...one other option(?) that many Canuck trucks had factory installed were block heaters. I don't know much about those. Never had the need for one. When I first heard that term I thought it was in reference to a wool cap. ('Toque')

The 9.5" semi-float "14-bolt" is way stronger than the "truck" "12-bolt" axle.

The Truck 12-bolt was not as strong as the passenger-car Chevy-design "12-bolt".

AND the squarebody axle doesn't fit properly.
AND the 9.5 semi-float is a direct drop in from (6-lug) GMT400 K2500 to GMT400 K1500 except for the rear U-joint. (You'll need the mounting plates that come with the 9.5 axle, and new U-bolts.)
AND you get better rear brakes with the 9.5.

Putting in a "12-bolt" is nuts.
Spending money to repair an 8.5" axle is nuts.