before sealed bearings were used, we had tapered roller bearings, they were used on front axles, cars & 2x4 PU & rears of a FWD cars. they would mount on a spindle (non- rotating shaft). the spindle would be threaded, so you could preset the pressure on the bearings then lock the nut. That is sometimes done with a cotter pin in a cross drilled hole. Even dodge had a grease fitting to lube them right on the truck such as a 79, 4x4 front axle.
The only thing you need to worry about on your rear axle is 1: good lube and proper level. Front axle is sealed bearings-no lube required.
2: however if you change rear axle brake shoes (I know you are lucky to have discs), then you need special socket to remove the lock retainer & nut to remove the drum and learn how to set the preload on reassembly.
If you need to replace a bearing, the inner or outer race must also be replaced (it is the other half of the bearing). the race is held in place with a press fit, so more special tools and skill required.