I think that I have a bad front output shaft bearing on my NP231. It's either that or u joints....here's a video I made of it.

http://www.youtube.com/watch?v=7uWQ7...ature=youtu.be

drop the driveline check the u-joints and see if they're seized. why the drive shaft is down spin the yoke and see if you still hear the noise.

I haven't pulled the shaft yet, I'll have to do that tomorrow when I have time to. Basically I'm getting a clunking and popping sound when driving.

sounds like U-joints.

Check the axle ujoints also

I'm pretty sure its u joints. Gonna rip it apart tomorrow and see what I can find

Did you ever figure out if that was the output bearing or the u-joint as I have the exact same sound coming from my 94 xj?