Dear All: I am Jack from Hong Kong, I got a ZZE123 1800cc 6M/T for around 1 years, i got some problem with my gearbox. When my car running at 90 - 100/km using 6 gear, when i want to change to 5th gear, it got not smooth and with "cack" noise from the gearbox. But if the change gear speed from 6th to 5th slowly, the noise become lighter. Only 6th to 5th got this problem, all others normal. I have changed few times Gearbox oil, Redline, Motul.. But the problem still occur. Is there any one face the same problem? is there i want to change my gearbox? Please help me. Best Regards Jack