We were out with some other rigs, doing some mild wheeling and I lost 4 wheel drive.  I will look into it more in the daylight, but it may be the auto hubs are not locking.

I have waited to replace them, because they have always worked without any issues.  The hubs are all steel, except the outer cover.  What goes wrong with them?  They were recently cleaned and lubed and we are still in the 70s here. 

I will tear them down this weekend to see what happened.  If I find something drastically wrong, I will replace them with manual locking hubs.  What should I look for?  Are the Warns the best way to go?

Are the Warns the only way to go?

Factory fit are Aisins, which may be available used, if you do get these, be certain to get the cone washers as well, if you're going aftermarket, Warn is only one of many options, google "freewheel hubs sidekick" and take your pick - I'm running SuperWinch which I believe is a rebranded Brazilian made AVM.

Thanks Foredom. 

I was debating between the Superwinch and the Warn hubs.  The SW hubs seem well made and they are noticeably less expensive.  I am hoping to figure out what the issue is with my factory hubs sometime in the next few days.

I installed my Superwinch hubs this morning.  They appear to be well made and came with gaskets for the front and rear.  They are so much less complicated than my auto hubs. 

No more wondering if I am in 4WD or not.  I should have changed them out a long time ago.

I would have gone with the Superwinch hubs as well.  I haven't been happy with my Warns at all.  Once they get buggered up they aren't rebuild-able.