Automatic transmission — removal and installation (BMW 3 Series E46)

Note: This is a very complex operation. Please read this manual carefully and purchase a winch and/or hydraulic lifting equipment before beginning. You will need a torque converter alignment tool and new O-rings for installation.

Removal

1. Disconnect the cable from the negative battery terminal (see chapter 5A).

2. Raise the vehicle and support it on supports (see "Lifting and installing the car on supports"). Please note that the height of the vehicle must be sufficient to allow the trolley with the gearbox to be rolled out from underneath it. Remove the screws and the engine/gearbox sump guard.

3. Remove the bolts and remove the front amplifier.

4. Remove the starter (see chapter 5A).

5. Remove the exhaust system and heat shields, then remove the exhaust support from under the vehicle.

6. Remove the driveshaft (see chapter 8).

7. Drain the transmission fluid (see paragraph 9).

8. Unscrew the fitting nut and disconnect the pipeline (if it exists) transmission hydraulic system reservoir.

9. Disconnect the selector cable from the gearbox (see paragraph 3).

10. Disconnect the electrical wiring connectors from the gearbox, noting their location. Release the electrical wiring harnesses from all fasteners to the gearbox.

11. Remove the oxygen sensor from the transmission bracket (if it exists).

12. Disconnect the transmission fluid cooling system brackets and clamps. Disconnect the lines (prepare for fluid leakage).

13. Remove the plug from the hole in the adapter connecting the gearbox to the engine (the plug is located above the tray) or from a hole in the crankcase (depending on the model) to access the torque converter mounting bolts (fig. 5.1, a, b).







14. Remove the three torque converter mounting bolts by turning the torque converter or crankshaft.

15. Place a hydraulic trolley with a wooden block under the gearbox.

Caution: The transmission is very heavy, so the support must be reliable.

16. On six-cylinder models, remove the heating/ventilation duct from the rear of the engine compartment as follows.

• a) Remove the cabin filter cover by turning its latches 90° counterclockwise. Pull the filter out of the housing.
• b) Unfasten the four fasteners of the cable management box and remove the sleeves with wires from the box.
• c) Remove the four screws and pull the cabin filter housing forward.
• d) In the left rear corner of the engine compartment, pull the seal, turn the two fasteners counterclockwise and move the trim panel forward slightly.
• d) Remove the two screws and remove the air duct.

17. On models with the M43TU four-cylinder engine, remove the bolts, remove the ignition coil and move it to the side. This is done to prevent damage to the high-voltage circuit of the system.



18. On all four-cylinder models, support the engine with a hydraulic jack. Place the jack under the engine pan, placing a block of wood between the jack and the pan. Raise the jack until it touches the pan.

19. On models with a six-cylinder engine, attach a winch to the engine rigging eye. The eye is located on the left rear corner of the engine (on the rear end of the cylinder block).

20. Remove the bolts of the front gearbox support (if it exists) (Fig. 5.20).



21. Make sure that the engine and gearbox are securely supported, then loosen the nuts securing the gearbox to the supports.

22. Remove the bolts securing the gearbox support to the body. If necessary, remove the exhaust system heat shields.

23. Using a jack (or winches) lower the engine and transmission so that the engine passes under the engine bulkhead. Make sure that the engine does not interfere with the cabin heating system hoses.

24. Remove the gearbox-to-engine mounting bolts, remove the washers, then slide the gearbox back.

25. Insert a metal or wooden block into the gap between the engine and the transmission housing to support the torque converter. After the transmission is disconnected from the engine, check again that the engine does not interfere with the cabin heating system hoses.



26. Lower the transmission and roll it out from under the vehicle on a dolly. Be careful not to drop the torque converter. If the transmission is being removed for an indefinite period, ensure that the engine is securely supported.

27. To remove the torque converter, first remove the block holding it.

28. Insert two long bolts into the torque converter mounting holes and pull them to remove the torque converter from the transmission (Fig. 5.28). Pull both bolts simultaneously. Be prepared for fluid leakage.

Installation

29. Install the torque converter. Using two bolts, rotate the torque converter so that it occupies the desired position. First, rotate the torque converter so that the splines of the hub align with the splines of the input shaft. The depth of the torque converter relative to the end of the housing exceeds 30 mm.

30. Make sure that the gearbox centering pins have not fallen out of the engine.

31. Before installing the gearbox on the engine, align the torque converter with the flywheel, since after installing the gearbox, the torque converter will not be able to rotate.

32. To align the torque converter with the flywheel, a special device is used, which is attached to the flywheel. You can make a homemade device from an old torque converter mounting bolt by sawing off its head, or from a stud of suitable length. Keep in mind that the device must have a slot or hexagon so that it can be unscrewed after installing the gearbox on the engine.



33. Turn the flywheel so that one of the torque converter mounting holes is at the bottom (to provide access to this bolt through the hole in the crankcase). This will allow you to remove the stud after installing the transmission.

34. Screw the centering tool into the flywheel hole (fig. 5.34, a, b).





35. Remove the block that held the torque converter in place.

36. Make sure the gearbox is securely fastened to the hydraulic trolley and roll it under the vehicle.

37. Rotate the torque converter so that one of its holes aligns with the centering device and install the gearbox in place.

38. Make sure that the tool fits into the torque converter centering hole, then insert the gearbox mounting bolts to the engine, placing washers on them (Fig. 5.38).





39. Remove the tool from the flywheel, then insert the torque converter-to-flywheel mounting bolt. Tighten the bolt to the specified torque.

40. Turn the engine crankshaft and insert the two remaining torque converter mounting bolts. Tighten the bolts to the specified torque.

41. The rest of the installation procedure is carried out in the reverse order of removal. Please note the following.

• a) Tighten all fasteners to the specified torque.
• b) Check the condition of the sealing tracks of the transmission pipelines; replace them if necessary.
• c) Install the propeller shaft (see chapter 8).
• d) Install the starter (see chapter 5A).
• d) Connect and adjust the selector cable (see paragraph3).
• e) After finishing work, fill the transmission fluid (see paragraph 9).