Automatic Transmission
Once there is a fault in the automatic transmission, it shall be sent to the factory for maintenance in time. It is not allowed to operate with fault, so as to avoid greater loss.
There are many tools used to repair automobile automatic transmission, generally including the following: internal and external hexagonal wrench, socket, torque wrench, pliers, gun, file, tap, bearing, bushing, locating ring pliers, electric wrench, ratchet, Jack, safety support, electric elevator, dial indicator, feeler gauge, multimeter and fault detector. The routine inspection items of automobile automatic transmission include: automatic transmission oil level height inspection, oil quality inspection, automatic transmission oil leakage inspection, engine throttle opening inspection, selector handle gear inspection, automatic transmission control switch operation inspection, engine idle speed inspection, etc.
Fault Diagnosis and Detection Procedure: preliminary inspection → fault code inspection → manual shift test → mechanical system test → hydraulic system test → electronic control system test → check common faults, cause analysis and troubleshooting.
1. Confirm the fault phenomenon according to the fault phenomenon analysis.
2. If it is an electronically controlled automatic transmission and the fault indicator is on, first conduct self diagnosis, read the fault code and eliminate the fault represented by the fault code.
3. Carry out routine inspection of automatic transmission and engine, mainly including:
a. Check the oil level and oil quality.
b. Check and adjust the accelerator pedal cable and throttle position sensor.
c. Check the linkage linkage of the selector handle.
d. Check the neutral start switch and gear switch.
e. Check the engine idle speed.
f. Check the tire pressure and other relevant parts of the power train.
4. Conduct stall test and check the internal mechanical and technical conditions of engine and automatic transmission.
5. Manual shift test; Determine whether the fault is in the electronic control part or in the automatic transmission.
6. Conduct time lag test to check the wear of clutch and brake of daily transmission.
7. Electronic control system self diagnosis and component and circuit detection.
8. Oil pressure test, check the oil pressure of oil pump, pressure regulating valve, governor and oil circuit pressure.
9. Conduct road test to check the automatic shift point, abnormal noise, vibration, slip and the braking effect of the engine.
10. Analyze and judge the cause and location of the fault based on the test results.
Matters Needing Attention:
1. The failure of automatic transmission is related to engine, electronic control system and automatic transmission. Therefore, it can be disassembled and overhauled only after it is confirmed that the failure is inside the automatic transmission.
2. When lifting or supporting the vehicle, if you only need to jack up the front or rear of the vehicle, you must plug the wheels with triangular wood.
3. To disassemble and inspect electrical components, remove the negative terminal wiring of the battery first. After removing the negative battery wiring, the audio system and anti-theft system may be locked, and some system setting parameters may disappear. Therefore, relevant records must be made before power failure.
4. When replacing the fuse, the new fuse must have equivalent current intensity, and the fuse exceeding or lower than the specified current value cannot be used; A digital multimeter with appropriate range shall be used to check electrical components to avoid damage to parts.
5. Before disassembling the automatic transmission, thoroughly clean the outside to prevent dirt from polluting the internal parts. Even small sundries can cause faults in the hydraulic system of the automatic transmission.
6. When disassembling the automatic transmission, all parts shall be placed in order to facilitate reassembly. Especially when disassembling the valve body assembly, the valve shall be placed together with the spring.
7. Thoroughly clean all parts of the disassembled automatic transmission, and blow through all oil passages and oil holes with compressed air to ensure that they are not blocked. It is recommended to clean the parts with automatic transmission oil or kerosene. Dry it by air drying after cleaning.
8. Before assembly, carefully check all parts and assemblies, and replace damaged parts if found. If assembly
9. Disposable parts can not be reused, such as cotter pins, sealing elements, etc.
10. When the bushing needs to be replaced due to wear, the supporting parts must be replaced together.
11. Needle roller bearings and race raceways are worn or damaged and should be replaced.
12. When replacing new clutch and brake friction plates, they must be soaked in automatic transmission oil for at least 15min before assembly.
13. All sealing rings, rotating parts and sliding surfaces shall be coated with automatic transmission oil before assembly.
14. Grease (grease) can be used to stick small parts in the corresponding position for assembly.
15. All needle roller bearings and race raceways shall have correct positions and installation directions.
16. Do not use sealant on gaskets or similar parts.
17. All parts and assemblies shall be assembled in the reverse order of disassembly; The screws shall be tightened to the specified torque.
18. Special tools shall be used as much as possible in all disassembly and assembly processes.
19. Check the hose and wire terminals to ensure correct and reliable connection.
Post time: Oct-21-2021