gearbox removal

hi there after noticing a leak from gearbox that was dripping off the prop shaft i decided to replace seal in gearbox where the prop goes into,well after another inspection it still has the leak it seems to be coming from above the prop and running down onto it so i have decided to remove box to give it a good looking over how hard is it to remove box and where would this leak possibly be coming from?? thanks.

gearbox is easy enough to remove but you will need to unbolt the remote lever part off the back otherwise it will not give enough room to drop box out