Toyota Corolla

1992-1998 of release

Repair and operation of the car

Toyota Corolla
+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engines
+ 4. Cooling systems, heating
+ 5. Fuel, exhaust systems
+ 6. System of decrease in toxicity
- 7. Transmissions
   + 7.1. Mechanical transmission
   - 7.2. Automatic transmission
      7.2.1. Specifications
      7.2.2. Diagnostics
      7.2.3. Replacement of epiploons
      7.2.4. Rope of a butterfly valve
      7.2.5. The switching rope
      7.2.6. The switch blocking inclusion of a starter by the included transfer
      7.2.7. Fastening of a transmission
      7.2.8. Removal and installation of a transmission
+ 8. Coupling and half shafts
+ 9. Brake system
+ 10. Suspension bracket and steering
+ 11. Body
+ 12. Electric equipment

7.2.2. Diagnostics



Malfunction of an automatic transmission can be caused by five general reasons: bad operation of the engine, the wrong adjustment, malfunction in hydraulic system, mechanical malfunction or malfunction of the computer or its alarm system.

Diagnostics of these problems always needs to be begun with check of the next moments which are easily giving in to correction: check the level and quality of liquid of an automatic transmission (see subsection 2.7.5), check adjustment of the connecting mechanism of a transmission and butterfly valve. Further, pass on the car and check, whether malfunction was eliminated or it is necessary to continue diagnostics.

If after carrying out preliminary checks and adjustments malfunction was not eliminated, further diagnostics of a transmission needs to be entrusted experts. Cm. subsection 1.5.36 for obtaining information on the reasons of malfunctions of a transmission.

Preliminary checks

1. Pass on the car to warm up a transmission up to the normal working temperature.
2. Check the level of liquid of an automatic transmission.
3. If the level of liquid is lowered, add liquids to the demanded level, and then check a transmission for tightness (see below).
4. If the level of liquid is increased, merge surplus, and then check the merged liquid for availability in it of cooling liquid. Availability of cooling liquid of the engine in liquid of an automatic transmission testifies that the walls of an internal radiator dividing cooling liquid and transmission liquid lost tightness (see subsection 2.3).
5. If transmission liquid foams, completely merge it from a transmission and fill in new, then check old liquid for presence at it of cooling liquid of the engine, and also check, whether the level of transmission liquid in a transmission increases.
6. Check the speed of operation of the engine in the idling mode.


If the engine is faulty, do not carry out preliminary inspections until it is repaired and will begin to work normally.

7. Check adjustment of a rope of a butterfly valve. Adjust it if it is necessary (see subsection 7.2.4).


Adjustment of a rope of a butterfly valve can be correct when the engine is switched off also cold, but can not correspond demanded during the operation of the hot engine. Check adjustment of a rope in both cases, when the engine cold and when it is heated-up up to the normal working temperature.

8. Examine the switching transmission ropes. Check that they were correctly adjusted and went freely (see subsection 7.2.5).

Tightness check

It is easy to find the majority of leak of transmission liquid visually. Repair usually consists in replacement of an epiploon or laying. If it is heavy to find leak, arrive as follows.

1. Define, what liquid proceeds. Be convinced that it is transmission liquid, but not oil of the engine or brake fluid (liquid of an automatic transmission has red color).
2. Try to establish a leak place. Pass some kilometers on the car, then install it over a big sheet of paper or a cardboard. In one-two minutes you will be able to find a place of leak of the liquid dripping on a cardboard.
3. Carefully examine places, from where there can be a leak, and area round them. Pay special attention to connections in which laying is used. For survey of hard-hitting places, use a mirror.
4. If you nevertheless do not manage to find a leak place, carefully clear area where perhaps there is a leak, by means of an obezzhirivatel or solvent, and then wipe it dry.
5. Pass on the car some kilometers at various speeds at a normal working temperature of a transmission. Then, again examine area where, perhaps, there is a leak.
6. After leak detection, it is necessary to define its reason. If you replace laying, but edges of connection will be bent, new laying will not eliminate leak. The bent edge needs to be evened.
7. Before leak elimination, check that the following possible reasons of emergence of leak were eliminated as they can lead to formation of leak again.


Some of such reasons can be eliminated only by means of the special equipment and existence of the corresponding experience. At detection of such malfunctions, address to experts.

Leaks through laying

Periodically check the oil pallet. Check that bolts were reliably tightened, there were no the absent bolts, laying was in a good shape, and the pallet was not bent (dents on the pallet can testify to existence of damages to the block of valves inside).

If laying of the pallet proceeds, so the level of liquid or its pressure can be too high, the outlet can be closed, bolts of fastening of the pallet are tightened too hardly, edges of the pallet are bent, damaged edges of a case of a transmission, laying or a case of a transmission is damaged can be will burst or to have a porous wall. If instead of laying between a case of a transmission and the pallet sealant was used, it is possible that incorrect sealant was applied.

Leak through epiploons

If transmission, any of epiploons, proceeds, so the level of liquid or its pressure can be too high, the outlet can be closed, the nest of installation of an epiploon can be damaged, the epiploon can be damaged or incorrectly established, the surface of the shaft passing through an epiploon can be damaged or the worn-out and loosened bearing can cause the excessive, free movement of a shaft.

Check that the probe tube epiploon for measurement of level of transmission liquid was correctly established. Periodically check area round the drive of a speedometer or the sensor of speed for existence of traces of leak. If they are present, check a sealing ring for existence of damages.

Leaks through a case

If the case proceeds, so case walls porist, and it needs to be repaired or replaced.

Check that connections of hoses of cooling liquid were reliably tightened and in a good shape.

Liquid follows through a tube of the outlet or a tube of filling of liquid

It means that liquid level in a transmission is too high, cooling liquid mixes up with transmission liquid, case walls porist, the probe is incorrectly inserted, the outlet or drain channels is closed.