jsarms21

My 2008 STX 4.6l 4wd has developed a mysterious rattle that really drives me nuts. Well actually there's two different​ rattling sounds but one​ is concerning due to it sounding like it comes from the transfer case. It sounds as if it's almost a grinding sound more than anything while driving around but if I grab my 4wd shifter the sound seems to change. Also the sound is louder and more noticeable first thing in the morning when I drive for the first that day. Any ideas on what may be causing the sound? My truck is lifted with 35x12.5 20s if that helps.