Hi Al. There were none of the obvious warning signs that others have noted on here (whining in sixth etc.) – and it didn’t go in a big way.
It deteriorated over the course of a 45 mile drive from Lancaster to Barrow. It was absolutely fine when I set off, developed a whine (quiet at first, but got louder) after about 20 miles, starting jumping out of 2nd and 5th gear after that, and for the last few miles was virtually undriveable, very difficult to get into 1st, 2nd or 5th gear and making a racket in those gears.
My recovery company wanted £211 to take it back to Lancaster
so it went to a garage in Barrow who changed the gearbox oil, took it for a couple of test runs, and thought they’d sorted it
I drove it home Friday evening and it was fine most of the way, until I engaged sixth on the motorway when the whine developed again, though not as loud as it had been on the Wednesday. I used it for a couple of short runs on Saturday morning, when it was whining in second, then it dumped a couple of litres of gearbox oil on the road outside the house
Back to my usual garage this week, a short run later they decided something was badly wrong inside it, which would only be fully apparent once it was stripped down. It was when removing it from the car that they found the fractured casing.
So the gearbox is off to a specialist in Preston for a strip down and rebuild, but of course a replacement casing is required which may pose a problem…