He means transfer box, and he can't bleed it, I forget the grade of oil that goes in it but no dot drive with no oil in transfer box, he should have done this for you as when it was brought to him there was oil in it, if he is a gearbox specialist this should be child's play for him
The gearbox doesn't need diff oil. Are you talking about the transfer box which connects to the gearbox via an output shaft? Who took them off the car? As they should be putting them all back with all oils