Need HELP!! np203

[Jaysonb]

My truck has a np203 that has been converted with a part time kit before I got the truck. The 4 wheel drive has worked fine for the last year, but yesterday i locked it in, and only had 2 wheel drive, and I could hear a noise like something was only partially engaged. The front axle would engage sometimes. I put it on the lift today, and the linkage is adjusted fine, and my shifter is clean, and works fine. Are the bearings in the part time kit that take place of the spider gears prone to fail? And if they did would these be the symptoms? The main chain must be ok, the front axle did engage intermittently. With the truck on the lift, and the linkage from the shifter removed, I would lock it in 4 and the front and rear drive shafts would move together like they should, but take it off the lift and not change anything, and only rear wheel drive. Any help is appreciated.