follow up after one year.  after a few thousand miles it started groaning, then got louder. made it about 10,000 miles before it got demoted to me driving it (instead of my wife).  i drove it about a month before the transmission locked up in the driveway - how convenient, i didn't have to get the truck and trailer!

 

it's on the floor of my garage and i've got a replacement trans i'm cobbling together to repair it. hopefully back and driving soon.  replacing all the H6 timing guides, tensioners, water pump while it's all apart too.

since this issue is so rare and very difficult to DIY - here's another person with the same issue:

http://www.ultimatesubaru.org/forum/topic/146646-98-outback-front-differential-retainer-didnt-mark-before-removal/