My gear stick is quite slack: i.e it doesnt bounch back into neutral when shifted out of gear very convincinly.

 

I'm unsure on how the Z box operates, would it be something like a retention spring or syncros ?

Edited June 10, 201015 yr by Sir Charles

ok if u look at some pics on me removing the upper cover u will see some steal rods with rounded ends there sprung protruding from the outer wall rods sit and slide on cut groves on the shaft

 

http://www.japnortheast.co.uk/forum/index.php?/topic/40304-gearbox-rebuild/

 

but i dont think thats your problem probably lower rubbers on gearstick or the ball joint is caked in crap try taking a look at that first mite need washing and regressing.