Just Wondering
 

I want to get full time 4 wheel drive right now i have part time. What do i need and how much work is it.

You want to convert your XJ to full time? If that's the case swap your t-case to a 242, than you'll have the best of both worlds. As for parts list all you'd need is a T-case to swap in all other parts are interchangeable. The only part that might be different would be the input shaft(in the t-case) But no worry you can use the one out of the t-case you have already.

junk yard? ballpark price? man hours?

I can do the swap in about 45 min. But I've done more than I can count.. For some one doing it for the first time your looking at about 4 hours give or take...

As for price I'd start with Craigslist I've seen them sell for any thing from $50 to $350 all depends on the market in your area. Shop around there are good cheap ones out there.

Junk Yard is a good place to find one but will probably the most expensive..