Vehicle: KIA smart run 2.4, equipped with G4KE engine, A6MFI six speed automatic transmission. Fault: the R gear vibrates when shifting out of P/N gear, and the other gears are normal. This fault does not affect the normal driving. Interrogation: the owner told the car that the vehicle had been overhauled at a repair shop a month ago because it did not run. It is normal after overhaul, but there is a distinct vibration when there is a R to P/N file when waiting for the red light. Verification: P - R is normal. R to P/N vibration. If the switch is fast between R and P/N, the fault vibration will be reduced. The other gear is normal. Maintenance process: the diagnostic instrument reads the related system. Without fault code, data flow and normal vehicle alignment are basically normal. Analysis: 35R clutch clearance too small, incomplete separation. 35R clutch release pressure is not fast enough. The oil plate assembly is wrong or damaged. From the simplified to the complex, first remove the oil road board. 8 solenoid valves are measured in comparison with the data, and the resistance values are all in the standard range. Carefully disassemble the oil plate, and finally find that the assembly is wrong. Solution: re assemble according to the manual, after several trial run, troubleshooting. Summary: for automatic transmission, I dare not publish too much, after all, the maintenance experience is relatively weak. Personally, it is necessary to be careful when it comes to maintenance of any part. Try not to make too many assembly mistakes. Again, data is important.