I have the same problem (or had - its currently out of action)
Didnt seem to select 3rd gear, but I wasnt sure of how to adjust, so had left it for later.
Just checking. For adjusting, your talking about the little grub screws in the centre of the 1/2 round GS068?
These are the little screws that push on the little steel balls next to the drive shaft?
Providing that I have that correct, what the preload you have to put on the little buggers on the sides of the 1/2 round clutch things (the screws with the springs in them)?

Ta...