Airwalk30

I have a 2014 f 150 5.0 supercrew I put a 2 inch rouph country leveling kit on it ( not sure if this is the cause being I didn't use 4wd until the flakes started falling) I have a loud clunk usually while going up inclines while 4wd is engaged dealership can't pin the problem had it their twice. Any others have this problem ? The clunk sounds like it's coming from front driveshaft pretty much right underneath me while driving. Any help would be greatly appreciated thanks