BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engine
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
- 8. Transmissions
   + 8.1.2. Specifications
   - 8.2. Automatic transmission
      8.2.2. Specifications
      8.2.3. Diagnostics of automatic transmission
      8.2.4. Draft of the selector of transmission
      8.2.5. kick cable - down - the mode
      8.2.6. The blocking backing signal switch/switch
      8.2.7. Removal and installation of transmission
      8.2.8. Epiploons of automatic transmission
      8.2.9. "Automatic machine"
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
+ 14. Useful tips


8.2.3. Diagnostics of automatic transmission



Malfunction of the engine (loss of power), wrong adjustments, refusals of hydraulic system of transmission, mechanical drive and processor control system can be the main reasons for abnormal work of transmission. First of all it is necessary to check the level and a condition of liquid, to adjust draft of the drive and the gate. If these measures do not result in positive result, then it is necessary to address to car service.

Preliminary checks

Make a trip to warm transmission.

Check the level and a condition of liquid (see subsection 2.6). If level is much lower than norm, then restore liquid level in transmission and check existence of leaks outside (see Check of a condition of transmission on liquid leak).

If liquid level in transmission is higher than norm, then check pollution existence by cooling liquid of the engine which could get to a cooler because of violation of its tightness (cooler is mounted in a radiator). If transmission liquid foamy, then merge it and check availability of impurity of cooling liquid in it.

Check a condition of liquid on the probe on color and a smell. Dark color and a "burned" smell indicates malfunction of transmission or violation of terms of change of liquid.

Check turns of idling of the engine. If necessary execute repair and adjust as further checking of transmission does not make sense.

Believe freedom of movement of a cable of kick - down - the mode.

Malfunction of a cable of kick - down - the mode can be shown only on the heated-up engine. Therefore check work of a cable at first on cold, and then on the heated-up engine.

Check adjustment and smoothness of movement of the drive of transmission.

Check of a condition of transmission on liquid leak

The liquid leak easily is established on dark red color and is eliminated with replacement of epiploons or laying. If leak weak. that carefully clear a case and check places of consolidations after a trip. For detection of a noticeable leak park the car after a trip on several km over the blank sheet of a cardboard or paper. About 2 min. later to flow it is possible to find. If a leak very weak, then it it is possible to establish on poteka, having absolutely wiped a case.

The leak communicates an air stream that complicates its detection. Therefore execute checks at various speeds of the movement, and also at the parking of the car.

If the place of a leak is established, then define the reason of a leak and a way of repair (for example, it is impossible to eliminate with replacement of laying a leak if the demountable planes are deformed).

Before elimination of a leak establish character and the reasons of a leak and define a look and volume of repair work as the set of types of repair independently cannot be executed. The most characteristic types of a leak are considered below.

The leak from under laying of the pallet can be a consequence of increase in pressure or level of liquid owing to a contamination of air vents, deformation of the pallet or its demountable plane, discrepancy of the applied brand of sealant recommended, defects of casting of the pallet, weakening of bolts of fastening, deformation of the pallet that can cause breakage of the block of valves of transmission.

The leak from under an epiploon can be caused increases in pressure or level of liquid owing to a contamination of air vents, wrong installation of an epiploon, injury of the condensed neck of a shaft or wear of the bearing of a shaft.

The leak of a case is caused by defects of casting. Check reliability of fastening of hoses of a cooler of liquid.

The leak from a sapun or from a filling branch pipe indicates overflow of transmission, hit of cooling liquid, wrong provision of the index, contamination of ventilating and drainage channels.