I'm sure this has been covered somewhere but I have looked for quite sometime and can't find the exact answer I'm looking for. I have had an intermittent "pop" when turning the steering wheel left or right. I dropped the steering column down last week to remove the dash and replace the heater core and it has since gotten worse. Before you could feel it in the wheel when it made its popping noise but now the sensation is more pronounced. I have replaced most of my steering components in the truck already and with it becoming worse after dropping the steering column I'm lead to think it must be in the column itself. Any ideas? The truck is a 01' 2500 4wd six speed manual. New parts include ball joints, adjustable track bar, tie rods and ends, and steering shaft.  

Just a REAL STUPID thought, don't laugh...How about the "clock spring" in the steering wheel?  I am having a similar noise and it's coming from inside the truck in the steering column/steering wheel.   I've heard about these springs and this may be in my future. Now I just need to learn how to fix it without popping the airbag.  I only say this because NWingert said it "sounds like a spring winding up and popping".