Had a look at this problem this afternoon.
Have bought an 88k mile auto box to investigate and then possibly get refurbed for my TD4 at 200k !
In the meantime I thought I would try to remove the high clutch / reverse drum which I think is the cause of the flaring on my 31k miler.
Photos below, but basically, clean off crap, remove 15 or so smaller bolts and a couple of large one.
Top is eased off and an internal spring helps it.
The first drum to pull off is the drum I need.
Refitting is trickier as you have to align all the clutch plate notches on both stacks. It's a bit like a Rubix cube, except you can't pull the coloured dots off and move them if you can't do it !!
Prepare to remove end plate.
Inside of cover when removed.
Inside of gearbox with cover removed.
Drum slides off ready for repair.
When I remove the faulty drum, I will strip it and check the reverse drum has a crack in it, but the circlips are under tension and with the failed one I won't have to put it together again !!!