Tried earlier this morning and with the engine running, Diff Lock in high and gearbox in 1st, all the gears in the tfer box were static/locked. I couldn't move them with the bit of wood I had been using apart from a bit of play. I moved the front prop by hand and the gears in the tfer box moved slightly as above as I expected (?). The back of the gearbox did sound a bit noisy though with the diff cover off. Another thing I noticed is that the higher the gear when changing (which I can do as it's on ramps/axle stands with no transmission), ie 1st to 5th in lock, the noisier the sound in the cab got (as though gears trying to mesh) but not very loud at all more of a rumble. No judders though.
....ideas please matey, many thanks, Tony