I believe I have two problems.
1. I can put the Jeep GC into 4WD (full time) while coasting yet while moving. However, it will not come out of 4WD when I move the shift handle back into 2wd (like it use to do when it was newer). I must come to a full stop and put it into reverse to get it out of 4wd. (I have not dared to put it into LO so I don't have any idea if it will shift in or out of LO.)
2. When it is in 2wd it runs smoothly and relatively quietly. When I shift it into 4WD starting about 30 mph, it becomes noisy. More of a low rumble (not a whine or a hum). It tends shake the steering just a little, but not as much as a shimmy when out of alignment. When I get it back into 2wd (see #1) its sound and feel is back to normal.
I have replaced the transfer case replaced. I have not looked at the front differential or any of the various universal or CV joints. I have not check on alignment (but the rumble noise is only while in 4wd).
Any suggestions on where to look to fix these problems.