One last question before I make my decision - how much should I be worried about the differential?

This truck runs fine, and sounds fine - so I am not suspicious of anything. But it is old, and things go wrong. Is the differential serviceable, can parts be found? I have been doing a lot of research, and found a lot of good information on this site. But if I would need ring or pinion gears at some point, or bearings or seals - is there a source? Or do I need to scrounge used parts? Does someone here know where parts can be found?

Is it easy to transplant something out of a more modern vehicle?

I want to give this truck a new home, and take care of it. Also want to enjoy it and run it. It would have an easy life - but I sort of need to know if I can take care of it (if that makes sense...).

Thanks for your help - this is not an easy decision.