i've lately been finding it harder and harder to shift into 2nd gear on my '65 bus. i can get in with some force from 1st gear but can't get in at all from 3rd , 4th or neutral. i've tightened the clutch cable as much as dare which did make it better, but hasn't solved the problem completely. i'm not sure if the problem is with the gear box or the clutch. i have also fairly recently changed the gear box oil. perhaps a better "quick shift" type gear stick would help? any suggestions and advice would be very much appreciated. thanks.