Choosing a new or used vehicle also means asking the question of its gearbox, which has become ubiquitous on the different models of the manufacturer. Comfort, consumption, maintenance: why can you choose a BMW automatic transmission?
Certain elements should not be overlooked when choosing a vehicle: either according to its budget as in this article presenting the BMWs accessible for a rent of 350 euros per month , or according to its use and engine as here with the 20d engine , we finally end up wondering if it would be better to choose a manual gearbox, or an automatic gearbox. Deemed too expensive , impractical, not sporty or responsible for overconsumption of fuel, it is time to take stock and restore some truths about automatic transmissions. If the sporting approval of a mechanical gearbox is indisputable, the automatic also has a say in this endless duel.
With the current development of new techniques , the automatic transmission is gradually democratized and has become an alternative on entry and mid-range models. It is no longer the preserve of only high-end models . Indeed, the strongest (or most noble) engines were confined very early to the only automatic gearbox, symbol of modernism and of a driver preferring to do other things of his time than to handle a lever. Mentalities are changing : at a time of task automation and driving aids, the automatic transmission is on the rise.
BMW automatic transmissions
BMW currently offers a six or even eight-speed Steptronic torque converter gearbox on its new models. Launched in 1994 on the 850Ci, the model has evolved and improved over time. This gearbox, developed by ZF ( like Alpina on its models like this B5 to discover here ) was first offered on the BMW longitudinal engines.
Before the democratization of Steptronic, there was the DKG , manufactured by Getrag. First introduced on the BMW M (like the M3 E9x ) in a special version M DKG (or M DCT), it had 7 reports installed in two partial boxes, one dedicated to peer reports and the other for odd ratios and each having its clutch disc. These dual-clutch transmissions were complimented for their speed and efficiency since they combined the advantages of a mechanical transmission with the advantages of an automatic transmission. But their complexity and the advances made on converter boxes like the Steptronic push them towards the exit.
Even older, the SMG gearboxes (photo below), SMG-C and SMG-II were robotic transmissions (five or six gears depending on their generation), halfway between a mechanical gearbox and an automatic gearbox . Slower than a DKG, it is an electro-hydraulic system which takes care of disengaging and shifting gears. Proposed for example on the M3 E46 which celebrates its 20 years this year , it will have marked its time! These boxes have a clutch system and therefore require maintenance, just like the DKG. These are the replacement of the clutch discs when they are worn and a periodic oil change specified by the workshop in charge of the overhaul.
The advantages of a BMW automatic transmission
It is therefore possible today to choose, on a BMW, between an automatic transmission and a manual transmission. The main advantage of an automatic transmission is the comfort of use brought to daily life since the driver no longer needs to disengage to change gear and therefore to play with his left leg in traffic jams.
Coupled with an active regulator as on the Series 6 Gran Turismo , it allows for example to adopt the good pace in traffic jams , until the complete stop and to restart automatically. This is a strong argument for the fervent supporters of the mechanical gearbox. Its technology is also used during the fully automated maneuvers of Park Assist, the operation of which is explained here , where the vehicle accelerates and brakes on its own. In situations of loss of grip , note that the gearbox management is in permanent communication with the vehicle\’s DSC system and with the software taking care of the xDrive intelligent transmission when it is present on the model.
The automatic transmission with torque converter (like the Steptronic) also has the advantage of smoothing gear changes and therefore eliminating the jolts between two gears, often unpleasant in manual transmission, even when the driver is gentle .
This smoothing of the transfer of torque and the use of the single right foot to accelerate and brake has a major advantage in urban driving , but has the disadvantage of making the engine brake disappear except to manually downshift with the paddles or the gear lever . It will therefore have to be accommodated on the first kilometers.
In conclusion: the automatic transmission, a technological miracle?
The other complaint that could be made about the automatic transmission is its lack of sportiness since it would take away from the pilot the pleasure that he may have in going up the laps and playing with the gear lever. Fortunately, the paddles on the steering wheel compensate for this loss, as well as the different driving modes, presented in detail here . In addition, the most modern automatic transmissions do not cause excessive fuel consumption . So why not be tempted?
Today, Steptronic boxes require little maintenance and prove to be reliable over time . There is no Steptronic automatic gearbox change planned by BMW thanks to the presence of a long-lasting oil over time. Only a check during routine BMW maintenance is necessary. But ZF nevertheless recommends emptying every 8 years, or every 80,000 to 120,000 kilometers approximately. Today, the BMW automatic gearbox has serious advantages allowing it to supplant the antilift clutch control and its classic lever . So why not switch to the automatic?