Bad Clunking when locked in 4x4

[jnightrod]

Always something with this trucks front end. When I lock the truck in 4 wheel drive there is a loud clunking noise that can be heard and felt throgh the floor boards. If I turn the tires left or right while it is in 4 wheel drive it gets really loud. Just pulled everything on the front end apart and all looks good. Here is what is new All 3 universals on front drive shaft, both wheel hub assemblys are a year old, all steering linkage is a year old. Bought the truck with 100k on the clock and it did not have the original ball joints up front nor stock u joints at the wheels. I checked those and the seem to be fine. Abouit a year ago a very light clicking noise could be heard while driving in 4 wheel drive at the beach. Since then did not use it much unless at the boat ramp. This past snow we had about a month ago I used 4 wheel drive at the clicking turned into loud thuds which is where I am now with it. Also just pulled the front diff cover off and everything looks fine in there. About 2 months ago I got an abs light referring to the front driver side abs sensor bad. The last time that happened the passenger side needle bearing in the hub went bad and wiped out the sensor, but like I said the bearings look fine. Is it possible that it could be the locking hub or transfer case? The truck is a 2003 F350 srw, 152k miles with a leveling on 33x12.50.