axle question

Yes, they can be replaced. You will need to ensure that there is no thrust plug in the center of your third member, as it is only required for the factory style bearings, and may prevent the axles from seating all the way with the sealed ball bearings.

The old bearings and retaining collar can be carefully cut off the axles, the new bearings and retainers need to be pressed on with a press and some heating of the retainer / cooling of the axle. They are quite tight and some care needs to be taken to make sure the axle is not damaged and that they are properly seated.