Transfer case problems

How can I tell if the plastic fork in my transfer case in my 2006 Hummer H3 is going bad. I have not had any adverse effects, would not mind getting it replaced or machining me a new one. I have alot of experience working on vehicles. It drives around good, I have just heard alot about this part. My father is a GM certified mechanic, I asked him and he told me that if it has no adverse effects then he would not help me pull the transfer case apart. I really dont know how to tell if it is bad.