Badger, one only greases the gearbox input shaft splines - and not the mating splines in the clutch disk. When inserting the gearbox shaft back into the clutch disk, it will get whatever it needs. If you put grease into the clutch disk, inserting the input shaft will push any excess grease out forward, where it will drop onto the clutch disk and/or pressure plate, contaminate them with grease, and you'll get clutch slippage and have to replace the friction disk.