Usually replacing gearbox is expensive. However, since myvi halfcut is easy to get and super cheap, it make more sense to replace it instead.

For halfcut, I read you can get it for less than RM500. So the workmanship is like more than the part itself. This is fine as it is a lot of work. Try to get more warranty for it. 2 weeks is too little for warranty.

If you opt for repair, all the rubber seals need to be changed since already open the gearbox. So it's better to overhaul and repair.