The automobile manufacturer BMW stands at the origins of the process of developing technically advanced vehicles, as well as mechanisms for them. This statement also applies to automatic transmissions. Typically, the conglomerate utilizes the developments of well-known companies specializing in the production of automatic gearboxes, with subsequent refinement for use on their own engines.
Before the introduction of six-speed automatic transmissions in BMW cars, the transmissions were considered reliable and practically indestructible. The repair procedure was mastered by specialists at service stations.
BMW 3 Series Automatic Transmission
BMW 318 models in the E46 body are equipped with a four-speed automatic transmission. Such transmissions are a continuation of the development of the 3130, which worked successfully until the 1970s. The 318 models of BMW in the E46 body can still be found today, undergoing a major overhaul after a certain period.
The transmission filter is used only once and is not subject to replacement. In addition, repair kits for gaskets, seals, and friction clutches are produced for this type of gearbox.
The hydraulic transformer has a relatively short service life, and almost all major repairs are associated with it. The contamination of the transmission, resulting in increased temperature and oil deficiency, as well as the failure of the hydraulic block and solenoids, are the consequences.
Insufficient oil pressure has a negative impact on the bushings, which are replaced as a set. When the oil pump bushing wears out, it can fail. The main sign of this is oil leakage from the seals. The service life of the braking band can be significantly increased by ordering a reinforced version.
Repair and cleaning are carried out once every 200 thousand kilometers. The most common problem becomes the aging of solenoids, with the pressure solenoid being the first to go out of working condition.
In general, the transmission is excellent and can serve for a long time, and after repair, it can last just as long.
BMW 5 Series Automatic Transmission
The BMW 5 Series, in the E39 body type, was equipped with a five-speed automatic transmission. The gearbox is characterized by simplicity and reliability. It can withstand operation on contaminated or cold oil, as well as when the oil level is low.
If oil and its filter are replaced on time, the transmission can serve for a very long time without any malfunctions.
When using the transmission of this BMW model with insufficient oil level, after some time, the drum bushing of the front speed will be turned, causing the clutch drum itself to stop working. This applies exclusively to outdated versions of the gearbox because newer models have a bearing instead of a bushing.
The aging of the oil pump occurs a bit faster than the transmission mechanisms, and it can fail after just a few years.
BMW 7 Series
The BMW in the E38 body type was equipped with a five-speed gearbox designed for very powerful engines, characterized by a high torque. The gearbox was designed with a huge margin of strength for all its components.
The filter is for multiple use, with a service life of about 5 years. The period of use before the first major overhaul is about 7-10 years.
BMW X Series. This type of vehicles is equipped with six-speed automatic transmissions Hydra-Matic. The feature of this gearbox is its modular design, allowing installation on any vehicle — from compact minivans to high-power large SUVs.
The transmission of this model is characterized by relative reliability.
Common problems with this type of transmission are the pump cover and seal rings. The result of their turning is the appearance of jerks and delays when shifting gears. Damages to the sealing rings lead to pressure issues and a gradual failure of speeds 4 through 6.
With continued use of such a transmission, gears from the fifth to the third can fail. In particularly severe cases, all friction clutches, steel discs, and pistons can burn out. However, this is only possible with a severely worn-out gearbox.
The pistons are replaced only as a set and do not tolerate temperature increases. It is advisable to also replace the retainers at the same time.
The construction of the gearbox is not very reliable. The hub of such an element as its drum often breaks. The second common problem is the rapid contamination of oil and low pressure in the clutch, as it operates in a slipping mode.
Dirty oil harms the gearbox mechanisms. After 100-150 thousand kilometers, a major overhaul of the gearbox should be carried out, or at least check the seals for leaks independently.
