Possibly not the recommended way of undoing stiff nuts/bolts but I have found a long breaker bar and a small bottle jack do the trick without breaking sweat. Certainly works for the rear diff pinion nut when changing the oil seal.

when i changed mine recently i put the socket on the nut then placed a long crow bar between two nuts, turned until it touched the floor which locked the flange. just cracked the nut off then. easy peasy. LEE