Mao Mao, regarding your inquiry, in case of this kind of fault, the level and quality of gearbox oil should be checked first. Gear box oil should be changed every two years. Whether the level and quality of gearbox oil are normal. The key point is to check the shift control mechanism and check whether there are worn or loose parts in the shift control mechanism. If there is no problem, it should be the fault of the synchronizer in the gearbox, and the gearbox needs to be disassembled for maintenance.
See more [Suzuki Alto] information:/Suzuki-Alto/