Hi we have a 2012 1.0 citi go and we've had it in a skoda dealership as it wasn't going into gear with ease. They have said that 3rd gear seized onto the shaft due to over heating. No idea why it overheat however we are looking for a new gearbox now and have seen a gearbox with gearbox code OCF, however our old gearbox code is NZF, does the replacement gearbox code have to be the same as the previous one?? Thanks in advance.