The gears on my 200o astra envoy 1.7 tdi won't budge at all, we've reset the selecter box once but it has happened again. The car is stuck in 2nd as it happened when changing from 2nd to 3rd, but the gearstick is in the neutral position, I am completely unable to move it.

Does this happen to anyone else? Do you know how to fix it?

I thought it might be the selecter box itself and ordered a new one but what came was a gear remote and linkage - what I need is the bit that sits on top of the gearbox, has 4 bolts and a spring loaded button on it. When I describe this to people they don't know the name of it, so finding a spare is hard! Does anyone know what this part is called so I can try a spare?

Alternatively, does anyone have an engine diagram for this model so i can look it up in there?

Thanks in advance