Im very sure its the txb. looks like it is, but going to try tomorrow jacking it up trying each wheel i just find it strange that there is no warning light and no signs the box has gone other than it wont budge.
cant get all 4 off the ground as my drive is on a steep slope and would not want to try move it. basically when i went last night the car moved 2ft a bang which i thought was the engine then the car would not go forward or back. no light no fluid loss. there was a knocking noise when i pulled up in the morning.
If you unbolt one end of the prop shaft then see if the rear wheels will move, this will eliminate the rear diff, leaving it to be the gearbox or TX box more likely TX box and cheaper than a gearbox too.