Tom,

I wouldn't worry about the service that you did to the car. As long as the engine is running (you were able to limp home) the engine should be OK. From what you have described, I would lean toward the PSD stripping a gear. The planetary gearset that is driven by the engine or the sun gear attached to MG2 is what this is sounding like. Either way, they should fix it on Toyota's nickel.