Run Dry is a Qual., not something to bet yur butt on
Nick can correct me if I am wrong, but I believe that run dry does not necessisarily imply an impending gear box failure. It is a qualification. Thirty minutes with no oil pressure or the loss of oil. In some boxes the run dry qualification of the gear box requires residual oil in the sump and an aux pump operating. Also, a 30 minute run dry qualification implies no other gear box problems. i.e. fractured gears, bad bearings ….