Although luckily not many of us have to experience gear box issues it is one of those repairs that we all dread. You may not realise that there is a problem with your gearbox until it is too late or you may of noticed that it struggles to get in to gear a little bit but put it down to the clutch instead. Gearbox problems can be hard to diagnose yourself so you may need to take it to a specialist garage for them to have a look for you. You should not really have to replace a gearbox on a vehicle unless it has done a large number of mile but like any component on a vehicle, things can go wrong well before their time. A gearbox needs oil to run and if there is a slow leak you may not even realise until its to late. If the gearbox runs out of oil it will often be damaged beyond repair and will either need to be refurbished or replaced for a new one.
If you are considering buying a second hand gear box you should try and get at least a 12 months warranty with it as you do not want to have to be forking out for the same thing again a few months down the line. Gearbox replacements or repairs often cost in excess of £1000 so you want to try and avoid it at all costs.