I'm I to understand that in 10 years the C box only has 800 hours
No , it was rebuilt 1998 and I'm guessing 12 mths use then 2nd chip incident and they replaced the CGB with a new gearbox , it's been in an air conditioned store for 9 yrs
I don't know which chip detector sensed the metal particles , the logs just say making metal and the engineers there now weren't around when it happened.
The main reason for the post is to get a feel why it would happen so soon after a proper rebuild , it maybe one of those quirky alignment and clearance issues where everything is within spec statically but something is off when the gearbox is run.
Gut feel is something was wrong with this gearbox from day 1 and still is.
My guess is if it was rebuilt a second time a similar occurence would occur and it would be a headache for an operator in the future
The operator must have come to a similar conclusion and put another new CGB in the 412 it came out of.