12 bolt to a 10 bolt rearend bolt on swap?

[chris015]

Ok. So lil bro has a 87 "r10" 2wd. It has a 12 bolt 2.73 rear end. We put in a 700r4 and its lazy and lugs all to hell. Will a 10 bolt swap from a 12 bolt without any modifications?

Thanks yall. U saved my ass more then once.

[Palf70Step]

I don't think it is a bolt in swap. You'll probably need to change the spring mounts at least. I personally don't know of any 10 bolts that came in the 87 and older trucks, so I don't know what the width differences are (if any). It might be easier to change the rear gears to a 3.23, 3.42 or 3.73 gear.

[Myself]

Yes, direct swap. The 10 AND 12 bolt came in the 73-87 body style.

[sweetk30]

Originally Posted by Palf70Step

I don't think it is a bolt in swap. You'll probably need to change the spring mounts at least. I personally don't know of any 10 bolts that came in the 87 and older trucks, so I don't know what the width differences are (if any). It might be easier to change the rear gears to a 3.23, 3.42 or 3.73 gear.

what ? ? ? ....... 10 bolt rear was as common on 81-up as 12 bolt on 80-older was for 1/2 tons .

basicly direct bolt in IF 2wd to 2wd or 4wd to 4wd . for the lug count and the shock mounts .

brakes are the same pattern so if need be pull the shafts . swap brakes . new axle seals and install and run .

u-joint size might be different and need trick joint .

how did the 87 get the older 12 bolt ?

[Palf70Step]

Originally Posted by Myself

Yes, direct swap. The 10 AND 12 bolt came in the 73-87 body style.

I did not know that. I have never seen a 10 bolt in any of my squares. Learn new stuff all the time.

[79vette]

Originally Posted by Myself

Yes, direct swap. The 10 AND 12 bolt came in the 73-87 body style.

Agreed with this.

I have an 86 K5 that came with a 10 bolt rear (military M1009). I swapped the 12 bolt out of my 82 K5 a couple years ago, and it was a bolt in.
Somewhere between 82-86 the parking brake cable layout changed, so I had to swap the parking rear brake cables on my 82 12 bolt for the later style. And the yoke on the 12 bolt for some reason took a smaller U joint. But the axle definitely bolts up to the springs.

I didnt take a pic of the rear axle coming out, it was too cold... But I promise it did happen.

[mongocanfly]

my 86 had a 10bolt

[kwmech]

Why would you go backwards in strength? Do a gear swap and put in a posi at the same time

[79vette]

Originally Posted by kwmech

Why would you go backwards in strength? Do a gear swap and put in a posi at the same time

Agreed a gear swap and posi is probably better than swapping in another used axle in unknown condition.

But I don't know if a 10 bolt is backwards in strength. The 8.5" 10 bolt ring gear is 3/8" smaller in diameter, but the small pinion shaft and outer pinion bearing on the 12 bolt brings the suck. I don't think you're gonna break the ring gear, but losing a pinion on the trail would be a pretty bad time.

The only reason I swapped one into my truck is because it already had a selectable locker (ARB) in it.

[Just call me Sean]

I put a 10 bolt in place of my 14 bolt. Because money doesn't grow on trees.