you may have a yoke that the joints have went bad, and stretched the yoke, may have thrown a driveshaft and stretched it out. unless you go 3-4 inch suspension lift, you really don't need to lower your transfer case, most of the time,, if you lower your transfer case you need to shim you axel to keep both angles about the same. you'll know this when you take off and also when you let off the gas you encounter a shutter on the drive line. I found if you lift 2 inches a 2 deg shim works and for a 4 inch a 4 deg shim works. mine is lifted 4 inches I have a 1 inch drop in the transfer case with a 4 deg shim on the axel. anything more and I get real complicated with angles and drive shaft lengths.