Hi all
I can select a gear with engine off, with engine running then it wont let me select a gear. I have a 2003 2.5 awd petrol manual x type. do you think its my Concentric slave cylinder or something else. as its a 4 wheel drive will the gear box have to come out?

 

Sounds like clutch is not disengaging. I'd first check for leaks and bleed the clutch. If problem remains then it could be slave (concentric) or master cylinder. If you don't often drive the car it could also be a sticking clutch, but this is unlikely.