KYFordfreak,
Sorry to hear about your vibration problem. They can be a bitc% to resolve; however the TSB only applies to 4x2's. Have you checked your tires/rims for correct balance ? also you might want to change your ATF. Just my thoughts.
Good luck man.

 

Deacon
Thanks for the info. My reason for asking was that I thought there may be a similar bushing and seal setup at the back of my transfer case.
I have both things on my list to be checked out. Just haven't got to do them yet. I do not think it is a tire realted vibration, feels more like a bearing or in the driveline somewhere. Going to change the ATF, balance the tires, and change u-joints ASAP and go from there.