Steering Shaft Knuckle

[JR'Z 525]

I think I've chased down a clunking noise in my steering system down to the jointed knuckle between the steering gear box and steering shaft. I've been experiencing a little bit of wandering on the highway also. I jacked it up the other day and had the wife move the wheel back and forth. I felt and saw a noticable amount of play in the joint. Do this joint normally have play in it? Anyone ever replaced one? Any idea of the cost? Is it a pita to diy?
Thanks,
JR :(