Mmmm ...
Eric .....
You mention the 500 ... it too had some gearbox issues in the past ... vaguely remember an AD which required removing the Xmsn oil level sight glass and checking all the main gear attach bolts for loss of torque .... AND I found one (bolt) which had failed and was hanging by its lockwire!
Stopped taking transmissions for granted after that ( I think about 1977/8 IIRC).
