From a google search

http://www.circlip.com/

We have this image of the type of ciclip involved... (external)
http://www.circlipsindia.com/images/01.gif

hi chaps
this is well know problem I would rebuild the gearbox every 60,000 miles
If going on a big trip
take output bearing seal and detent springs
and the tools to take a gearbox out and replace the output seal easy to make before you go
cheers chris

thanx.
we also say "circlip" in french.
i was wondering if a drawing/picture was available to understand better what you re writing.

BMW manual
 

Is anyone still planning to make that manual available?
Sean