RealOEM.com * BMW E53 X5 4.4i STEER.COL.-LOWER JOINT ASSY
I had a similar clunk sound like something was binding whenever I make a left or right turn. No problem/sound when going straight, even on bumps.
I sprayed part #2 steering u-joints with lots of lube (BreakFree) and worked the steering wheel several times. To my surprise...the noise went away and now the steering is smooth and quiet. No more popping/clunking sound.
X has 122K miles on original steering parts.