Back on the road again...a LOT lighter in the wallet but running. I had asked the shop to save my parts so I could see what had happened to my trans, which they did. It was mostly a case of wear and tear. There was no "smoking gun" part that was the cause, just lots of metal dust in the pan and filter. The tech said that it's most likely that this dust jammed one or more of the plungers or other small moving bits causing fluid to go where it wasn't supposed to. This can cause quick clutch failures as well as other damage. Fortunately mine didn't grenade and just gave it up quietly.
Anyway, back on the road and still happy with my GTP!
joe