Here is the problem. I have a 99 xj lifted 6.5" RC, on 33" tire for the past 3 month or so i have this grinding noise coming out the front only wend engaged in 4wd Hi and LO. So here is the troubleshooting and fix that i did and the was no result of grinding noise fix.
1- change both front axle u joint
2- rebuilt and change all dana 30 front carrier and seal + pinion inner outer bearing and seal. and re-shim everything to correct spec.
3- rebuilt front drive shaft with 3 new u joint.

After all this the noise is still there, this noise seem the be worst wend the jeep front diff is under tension like going up hill in 4wd.

Anyone ever had this problem before I'm really tire of troubleshooting and no luck.

Here is a Video of the noise

 

Worst?

Wend?

LOL

The TC is dicked up.

Drain the oil out of the TC ino a clean pan and see if there's metal in the oil.

Aluminum=chain is eating the housing.

Steel=gears are ate up. Or metal-to-metal contact on rotating components.