The Truck Driver transporting that Gearbox in Australia died in the Accident.
So that will give you a good idea of what happened to the gearbox.
It's very possible the Conical housing was the initial cause. We may never know.
The fact the Gearbox was never scrapped, simply comes down to Greed!
Risk Analysis is a tricky game to play. Get it wrong and all of a sudden hundreds if not thousands of lives are effected and Millions if not Billions of loss come into play.
Those that get to play God in this way only ever get punished by way of the Karma God. It's a sad unaccountable World we live in.
Sikorsky made a mistake thinking there would always be oil in the 92 Gearbox.
Rubbish, this is a classic example of Greed and poor risk analysis at best