Examination (only a box with an oil filler tube)
Note: Since February 19901, some vehicles have been equipped with gearboxes without an oil dipstick (without filler tube). The oil level can only be checked by polling the status using the BMW service tester. Usually it is sufficient to regularly inspect the external part of the box and regularly replace the ATF.
Maintaining the prescribed oil level is very important for the normal operation of the automatic transmission.
The dipstick is located in the engine compartment. This is where the ATF is poured in (Automatic Transmission Fluid).
Attention: The test must be carried out with the box heated (+80°C).
Warm up the engine, the oil in the gearbox should have a temperature of about +80°C.
Place the unloaded vehicle on a level surface and tighten the handbrake.
During testing, the engine must be running at idle speed to fill the torque converter.
Set the gearbox lever to position "P" and tighten the handbrake.
During the test, the engine should be running at idle speed.
Remove the oil dipstick and wipe it with a clean rag without lint, or better yet, a piece of leather. Then insert the dipstick completely, pull it out again and read the reading.
At a normal level on a heated gearbox (about +80°C), the oil should reach the MAX mark on the rod.
Note: When the oil level is low, you can clearly hear air being sucked in. This causes the oil to foam and may give incorrect oil level readings. In this case, turn off the engine, add oil after 2 minutes, and then check the oil level again with the engine running.
Fill the oil through a clean funnel, preferably with a fine mesh. The difference in volume between the MAX and MIN marks is about 0.3 l.
Caution: Do not overfill the oil. If too much oil is poured in, the automatic system may malfunction. If the oil is overfilled, be sure to drain or suck out the excess oil with a syringe.
At the same time, check the oil on the dipstick for smell and color. Burnt pads give off a burnt smell. Contaminated oil can cause problems with gearbox control.
Caution: Only use ATF oil approved by BMW. In principle, all automatic transmission oils with the designation "Dexron II" are approved.
All approved oils can be mixed. Do not use any additives or supplements.
If the torque converter is not filled with ATF oil, do not start the engine or tow the vehicle.
After checking the level and topping up, reinsert the dipstick completely.
Press the brake pedal and slowly shift through all gears. Then check the oil level again.
The text is based on materials from the website «BMWman.ru»