noise in 04 front

[Blue Tank]

I liked my 72 burb so much i bought a newer one for a daily driver. 1/2 ton stablitrak,4wd 96k. The PO had the left front wheel bearing replaced a few months back. So when i heard a "pop corn" sound coming from the front of the truck i assumed the right one was ready. When i pulled the wheel and caliper the disc didn't move around like i expected so i put the tire back on for leverage and couldn't feel much if anything. With the trans in neutral and the rt front wheel off the ground you can hear a dry sound that seems to be from the front d shaft, the universals didn't seem loose by hand. The pop corn noise doesn't happen in reverse. The cv shaft felt ok. I changed the front diff fluid and it looked like 100k fluid should, no surprises.
1 Can you feel the hub bearing being loose short of grenade time?
2 Can this be from the spline shaft being dry in the t case? I see GM has a special lube for this.