A 2002 mileage Honda Odyssey with a mileage of over 220 thousand km and a MAXA automatic transmission. User response: the car will shake at 70km/h constant speed. After receiving the car: the fault symptoms are confirmed. The vehicle runs at a constant speed. When the torque converter enters the initial phase of the lock, the body jitter obviously; when the torque converter is completely locked, the body jitter vanishes. Check automatic transmission oil, oil and oil quality is normal. The automatic transmission system is self diagnosed by using the diagnostic instrument, and there is no fault code. At the same time, check the change of the data flow, it is found that when the lock clutch instruction appears, the body jitter appears immediately, and the skidding phenomenon is not appeared in the whole process. This shows that the transmission hydraulic system works normally, and the problem is torque converter. Remove the transmission assembly and check the torque converter. It is found that the torque converter has been refurbished. The flatness of the internal locking clutch face of the torque converter is measured, and the maximum fluctuation is not beyond the standard value. Check the locking clutch, the surface of the friction plate is not smooth enough, there is a convex part, which is caused by irregular operation when bonding the friction film. The common reason is that the mould used for sticking the film is not properly selected or the mold itself is not smooth enough. Replacement of hydraulic torque converter, the failure is completely eliminated. The unevenness of the clutch clutch friction plate is the direct cause of the body jitter. At the beginning of the lock clutch engagement, the friction plate is uneven, causing friction to jump, and joint impact to shake the car body. In order to ensure the quality of automatic transmission, it is important to use special tools to check whether the special tools are good or not. Unqualified special tools should be repaired or replaced as soon as possible so as to avoid such maintenance quality problems.