Sure you have the spring in the right way? Shouldn't have to loosen the other side, but if you drove it a while with the axle in crooked you may have to loosen the other side. Unless it's terribly rusty that should only take a minute.
I'm used to having a hoist, torch, and big impact wrench. If you're doing it on the ground it may take a few more minutes to loosen the four nuts.
You do have both rear wheels off the ground?
Last rear axle I swapped I used just a small MAP torch to heat the nuts. They're 50% hotter than propane. You shouldn't need acetylene.
I'm used to having a hoist, torch, and big impact wrench. If you're doing it on the ground it may take a few more minutes to loosen the four nuts.
You do have both rear wheels off the ground?
Last rear axle I swapped I used just a small MAP torch to heat the nuts. They're 50% hotter than propane. You shouldn't need acetylene.