I just pulled the axle as I need to change the diff seal.
I can feel a slight difference in resistance when moving the swivel hub from center position. Definitely feels like a worn bearing. But I did full swivel hub rebuild only 10.000km ago.
I did however not set a high enough bearing preload...
I'm not sure what the factory spec is for servicing/greasing those components.
The swivel hubs as we know are not a sealed space.
Tail/prop shafts can be a pita if grease nipples on them and uni-joints are in an awkward position.
I'm not sure about what the spec is for wheel bearing service...
First time that I've seen this type of coupler offered for sale in the US
https://econosuperstore.com/itm/3-5-ton-off-road-coupling-trailer-towing-swivel-coupling/