Separate characteristics are also given in the text of the Chapter and, if they are mandatory, are highlighted in bold
Common parameters | |
Type | |
Models 316i, 318i | 4-speed, with electronic-hydraulic control and ignition key lock functions (Interlock) and selector (Shiftlock), as well as an adaptive system (Steptronic). Fifth gear - overdrive |
Other models | 5-speed, with electronic-hydraulic control and ignition key lock functions (Interlock) and selector (Shiftlock), as well as an adaptive system (Steptronic). Fifth gear - overdrive |
AT with electronic control EGS/AGS | A5S 360R Siemens AGS 20 GM 5L 40E |
gear ratios | |
Gears 1/2/3/4/5/reverse: 1 | 3.45 / 2.21 / 1.59 / 1.00 / 0.76 / 3.17 |
Transfer ratios of the main transfer of models with АТ | |
Rear wheel drive models | |
316i | 4.44 |
318i | 4.44 |
320i | 3.38 |
325i | 3.23 |
330i | 3.38 |
320d | 3.07 |
330d | 2.81 |
All wheel drive models | |
325i | 3.23 |
330i | 3.15 |
330d | 2.93 |
Tightening torques for threaded connections | |
Fastener tightening torques are also given in the text of the Chapter and in some illustrations*. *The tightening torques in bold type are subject to exact observance; Efforts not in bold are indicative only | |
Beam to the bottom | |
M8 | 22 Nm |
M10 | 45 Nm |
Box to beam (M10) | 45 Nm |
Cardan shaft to box flange | |
M10, strength class "8.8" | 50 Nm |
M10, strength class "10.9" | 60 Nm |
M12 | 100 Nm |
Transmission control circuit temperature sensors | |
91° | 14 Nm |
99° | 14 Nm |
BMW 3 Series can be equipped with an automatic transmission (AT). In the process of starting off, the AT performs the function of an ordinary clutch, and while driving, it performs the work of shifting gears.
The main units of the AT are: a torque converter, a planetary gearbox and a hydraulic or electronic control system. To switch to another gear ratio in the planetary gearbox, hydraulic disc brakes and a disc clutch are used.
The torque converter has the same function as a hydraulic clutch. Its task is to carry out the clutch when starting off and shifting gears without mechanical impact.
The shift pressure is controlled by an electronic device instead of the hydraulics used in a conventional gearbox. Thus, there is more complete information for better control of the shift process, which makes it possible to select the optimal gear ratio depending on the mode of operation of the vehicle and the desire of the driver. The BMW control system in question is designated AGS (Adaptive Getriebesteuerung) (Adaptive transmission control system).
The control unit recognizes from the speed with which the pedal is pressed whether the driver wants to go "sports" or "economically" and controls the shift point accordingly. Shift control also takes into account driving resistance, such as whether the vehicle is moving uphill or downhill, braking acceleration and cornering.
Steptronic - automatic stepping
The 5-speed automatic has a short, step-shift gate next to the automatic shift track. Such switching is accepted in motorsport.
With Steptronic, the driver can shift up or down as desired. Compared to manual shifting, the Steptronic system is much more comfortable and error-free. For example, a gear shift is not carried out if the maximum permissible engine speed is exceeded as a result.
In the event of faults with the input signals or with the solenoid valves, the emergency operation program is switched over. At the same time, faults that occur during operation are recorded in the fault memory. Refer to Section Troubleshooting. It is desirable to carry out work in the conditions of a service station.
To evaluate the operation of an automatic transmission and to troubleshoot, a certain amount of experience is required. Therefore, only the removal of the gearbox and the adjustment of the selector rod are described here. The oil in the gearbox is replaced only during repairs. Oil change during maintenance is not carried out.
Cars with AT are allowed to be towed only subject to the established rules, refer to Section Jacking and towing.