I chickened out. I went by a local transmission shop. You know the type; they've been in business for decades and have transmissions, transfer cases, differentials and internal components everywhere. They're the real deal. They put my Denali on a lift and inspected the drive train. They verified that my transfer case chain is loose and slapping. They saw the multiple oil leaks. For $2200 they offered to drop and rebuild the TC with GM parts, undo the tranny and replace the RMS and rear engine seal (big, open square shaped seal), and reseal the engine oil cooler. Doing it myself I was going to be at about $1800 for a reman TC including tool purchases and tranny jack rental. These guys are a smarter solution for me.
Thanks again for your input.
Scott