1999 4WD steering knuckle - part ID

[AngerXL]

I'm usually good with the Googles on this sort of thing, but this time I'm stumped. There is a shield looking metal ring bolted on to the back of the steering knuckle that surrounds the CV axle. What is it and where can I find a new one? Parts store didn't know, speculation leads toward something ABS related.

 

[skyjack]

Let's revisit this post, because I have the same question. Anybody know what this is called and what it's purpose is? Thanks