Popping out of Gear???

[miles]

Well this old one, If you look at the old data you sometimes see 10/40 recommended and a gearbox I had from a so called gearbox reconditioner's said the same or the warranty would be invalid, But if you do use 10/40 the box will not last having seen the remains when people do, The old XY engine's are OK as the box is in the sump like a Mini.
Popping out of gear will either be box bearings or torque bush, Linkages just tend to fall off as the std ones cannot be adjusted