I haven't read it thru yet, but in the April 2008 Diesel World magizine there is an article about upgrading and repairing the HD transfer case. It looks like they are installing the new/aftermarket pump ring. There are pictures and torque specs. Looks like a pretty good "how to" article. I guess I'll get around to doing our 07 soon. I don't want the dreaded pump rub to happen while towing with horses 500 miles from home.
I have heard of the clips letting go with as little 6,000 miles on them. I know that most don't fail until they have 60,000 or more miles. But why take a chance.