can't change down gears

[egor110]

I've got a cliosport 172 cup, today I was unable to change down to 1st or 2nd unless I selected reverse first.

Any ideas as to what the solution could be?

 

[Cub.]

I'd check the selector rod underneath the car, check it hasn't had knock and gone out of position slightly.

 

[egor110]

Will check that out.

If it's not that I guess next up is synchromesh problem?

Is that a box out and gearbox rebuild job?
Is there any point buying a 2nd hand box when it could be as knackered as my current one.

Bit of a bigger as this year I've done the cambelt, dephaser, New clutch and changed the gearbox oil in a effort to keep the car in good Nick.