hi guys, i have a 98 grand cherokee laredo 4.0 that is popping from under the drivers floorboard when under power in 4wd or turning in 4wd. 2wd is quiet. full time 4wd is not as loud. i have replaced the wheel joints and the front drive shaft joints, no help. is it transfer case time? or is it the transfer case chain? it has a chrysler reman case in it that was already in there when i bought it in may 08, so i don't know how old it is. i hate to keep spending money and time throwing parts at it that it dosent need. i would really appreiciate your input on this. thanks for your time.