The assembled pinion shaft presses into the banjo housing through the big hole in the front, it is then secured in place by the torque tube flange, the big double nuts and locking washer are to set drag on the pinion bearings. There is one rear pinion support bearing and the main pinion bearing is actually two tapered bearings pressed onto the pinion shaft facing one another that share a common double tapered race, this race is what presses into the housing and holds everything together. I am unsure if the pinion assembly can be removed without first removing the ring gear?
33/34 is a slightly diffrent banjo housing than 35/48 and they do not interchange. Hotrodworks.com is a VERY good resource for banjo id. and information.
You can see the two smooth surfaces in front of the pinion gear that are seperated by a wide groove, this is where the bearings press onto the shaft facing each other. Banjo internals are really quite simple but I still had a pro assemble mine.