Block up the loader frame in the rear, unbolt loader rear arms from under back axle.
Block up front of loader, unbolt the front from tractor.
Disconnect everything else connecting loader to tractor (pump, etc., depending on how it is set up)
Lower rear arms slightly, pull tractor back until loader rear arms clear the axle.
Lift the whole loader frame until everything clears, then back the tractor out from under it. Probably use your cherry picker in the front, and a couple of floor jacks in the rear.