A serious 2.1?

[White Exec]

Fifth gear failures have been commonplace across many box manufacturers, even as recently as five or six years ago. The problem was the almost universal practice of hanging the "extra" 5th gear cog pair on the end of the shafts, without any bearing support on the outboard end.

Easy to replace (thousands of Toyotas had this too, including ours), as you say, by just whipping off the box end cover under the wing. Toyota issued modified parts to better resist wear, which has worked. Poor design, though.

[Peter.N.]

Cheap for the manufacturers though