All of a sudden Im having problems selecting 3rd gear, its been a very good gearbox for a Landy, very smooth and easy to select all gears but yesterday I started having difficulty going from 2nd to 3rd, coming down from 4th to 3rd is still as smooth as its always been.
Do any off you guys have any ideas ? Im thinking broken detent spring.

I'm thinking worn slipper pads in the third/fourth synchro hub. Or the gear lever bias springs not set up proply. Try pulling the lever slightly into the fourth position before pushing it up into third.

Hi,
To set the bias springs correctly, put gearbox in the third gear position and set both bias springs to a 0.010" gap (ten thou, same as tappets) between springs and lugs on bottom of gearlever.

Nige