Lound clunk coming from transfer case in every gear. Happens more often when under pressure (Pulling Hills, Accelerating) also when cornering. Sometimes it wont do it and then I'll hit  a bump and It will do it again. Clunk noises are about half a second apart and can be felt through most of the vehicle but i am sure its coming from the t-case because it doesnt do it in 4wd. Also I have new main driveline and U-joints, and front and rear drivelines are fine. HELP!!!!!

Sounds like you might have a gear or two with a broken tooth, does it sound like its searching to lock gears, locks in for a bit then spins and grinds again?

I just removed all my stock tcase gears to replace with the 6.5's so if you tear it down and find out you need something let me know, they can be had for cheap!

Try checking your Transfer Case Mounts.

Maybe a broken or missing rubber mount?

Maybe even a Bent Arm/Mount?

 Sorry for resurrecting this old thread but I haven't found anyone else with the same problem.

 Did you ever solve this? I have been having the same problem.  My old trannie died on me so i replaced it. Aftrt putting everythng back in, i suddenly have this repetitive clunking noise under throttle when in 2wd and moving. No noise in 4wd. Removed front propshaft, still noise in 2H and quiet in 4h and 4l. Removed rear propshaft. No noise in 4h of 4l. Have replaced joints in intermediate shaft because they seemed loose but didn't help.