Redo Stuffing Box on older 210

Whaddup guys were trying to redo our stuffing on the 02 super air (gt40) we just bought. The stuffing box was never changed since picked up from the factory and as you can guess there was a little more (read: spraying out) water than the couple drips a minute it is suppose to be. Were trying to loosen the jam nut but it wont budge. My friend told me that we should pull the driveshaft out completely but there has to be a better way.
Any tips or an online guide to do this?


Thanks
B