before you start thinking about removing g/box`s have a look at the clutch slave cyl at front of g/box,peel back the dust cover and if you see brake fluid,renew the slave cyl,had a couple of these where the slave cyl wasn`t giving the clutch enough clearance resulting in poor gear selection,another thing to look at is at the gear lever on the dash the metal frame mounting the gear change cables fracturing and cracking due to stresses,worth a look
cdc, June 2012