Vocho's speed box

I have a problem with a vocho box that boots the speeds ... I have disarmed other boxes from other manual cars but they say that the vocho boxes are difficult and I would like to know if someone can help me with photos or some tutorial to fix it ... Thank you ... someone told me that you have to synchronize them but in another hull of another box and open holes to be able to synchronize ... I wait for your answers ... greetings ...