Gear change issue!

[Lotusholic]

Hello all,i have a 91 se with 96500 miles on the clock.So my problem is that the gear changes are a little bit difficult,they don't stuck etc but they're not change easily especially when the car is stopped and i try to change gear from first to fifth,sometimes in this situation they don't even apply!I have in mind that the car needs gearbox oil,i have not change it for over of 25000 miles.Do you think that this is the problem??
Thanks

[rip]

The gears on the front shaft are known to sometimes come loose.
If you are going to change your gearbox oil anyway, then drain it then remove the gearbox end cover.
If you have caught it quickly, then tightening up the end bolts will do. If not, then some shims will have dropped between the gears. It is possible to re-align these without dismantling the gearbox, but I am not sure how.

Only the front bolt will be loose. The motion loosens the front & tightens the rear.
This is an occasion when 1 of the bolts should have a left-handed thread...but Isuzu never thought of that