Yes, it is possible to remove the gearbox without removing the engine. I did it last week-end (photo). I kept the exhaust system installed which prevents the engine from tilting excessively with removed gearbox. You have to remove the A/C cooler and tilt the engine a bit. Use a lifting device to remove the gearbox slowly. You will need every mm of clearance but it is just enough to remove the gearbox.
Brgds
SIG