I have a 2nd gen Ram 1500 with 5.9L magnum. I have the piso lock system and have rebuilt almost the entire np231d due to a grinding noise(best I can describe, loose ball bearings being pushed up and down the sides of the case). The noise was only when the front shaft was in motion. I took it for a test drive to see if the noise had gone away, shuffled through the 4x4 selector and about 10min into the drive the noise went away. About 5min later the mode selector got stuck on 4h.

 

What year is your truck? I didn't think any of the 2nd gens had an electronic shift t-case.

 

2000, it’s a floor shifter.

 

Try moving the shift lever while backing up. Usually that's a problem with the old full time, but the work you did may make your unit an exception.

 

Ok. If the above doesn't work, jack up the front of the truck, and try it.