The problem I have is with my 20 ton bottle jack and 12 ton jackstands there's no room to jack up one side and fit a jackstand in there.
I have the same problem. I fully understand Tigger's concerns and now I'm worried about breaking my diff housing. I have on many occasions, lifted the truck with a 20-ton bottle jack under the diff. I use (again I understand Tigger's concern and I'm re-thinking my method) a block of hard wood between the jack and the bottom of the diff. Yes, the block can split, yes I can see how the drain plug could be damaged, yes I can understand the jack-hammer effect of the air-powered bottle jacks. I've never had a problem, but that doesn't mean it can't happen.
There is enough room on the steer axle to lift on the axle tube and still get a 12-ton jack stand in there. The biggest issue for me is the middle axle. There is just not enough room to get the jack in there and a jack stand if you lift between the diff housing and the wheel. Plus, when you lift a rear axle, you're not really lifting weight of the truck. You're just over-coming the resistance of the springs and transferring weight to the other axle, right? I mean, I don't know how much weight that actually represents, but I know its a lot lighter/easier than lifting the front axle, even with a bed full of whatever. Still searching and thinking............