Hey! I'm suffering from the same....welcome to the club!!!
I have a 98 Explo 4x4 4.0 SOHC. It's like a humming noise, sometimes feels like a bump on the tire or a bad bearing.
Feels like coming from the driver's side.
I also changed new CV, tie rods ends, upper & lower BJ, new bearing hub, 4 new tires, and driver's side outer front differential bearing <--the one where the CV rest in.
I've read all the threads I've found on the internet and nobody gave with the cure. I was following a thread were the guy changed all the parts we also did and he was still with the noise, his last post said "I'm going to pull out the front differential and check it". Unfortunately it was his last post and the date said year 2007.
I suspect from the front diff bearings, other guy in a post said "If it's not the front differential, should be the transfer case".
At this time I'm looking for a front diff on local yunkyards to rebuild it myself with time and patience, will just change all the 4 bearings. But I didn't find one yet, it should be 3.55 gear ratio for me. And all I found are 96 and older which differs from mine 98. It believe it should be 97 to 01. Hope this help.