Individual characteristics are also given in the text of the Chapter and, if their implementation is mandatory, are highlighted in bold
| General parameters | |
Type | |
Models 316i, 318i | 4-speed, with electronic-hydraulic control and functions of ignition key lock (Interlock) and selector (Shiftlock), as well as adaptive system (Steptronic). Fifth gear is overdrive |
Other models | 5-speed, with electronic-hydraulic control and functions of ignition key lock (Interlock) and selector (Shiftlock), as well as an adaptive system (Steptronic). Fifth gear is 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 |
| Gear ratios of the main transmission of models with AT | |
| 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 forces of threaded connections | |
| Tightening torques for fasteners are also given in the text of the Chapter and in some illustrations*. *Tightening torques highlighted in bold in the text must be strictly observed; efforts not in bold are only approximate | |
| 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 |
The BMW 3 Series can be equipped with an automatic transmission (AT). When starting off, the AT performs the function of a regular clutch, and during movement, it performs the work of shifting gears.
The main units of the AT are: torque converter, planetary gearbox and hydraulic or electronic control system. To switch to another gear ratio in the planetary gearbox, hydraulically driven disc brakes and disc clutch are used.
The torque converter functions like a hydraulic clutch. Its job is to apply the clutch when starting off and to change gears without mechanical action.
The control of the pressure force during switching is performed by an electronic device instead of hydraulics used in a conventional gearbox. Thus, there is more complete information for better control of the switching process, which makes it possible to select the optimal gear ratio depending on the operating mode of the car and the driver's desire. The control system of the BMW company in question is designated AGS (Adaptive Gaining) (Adaptive Transmission Control System).
The control unit recognizes from the speed at which the pedal is pressed whether the driver wants to drive "sportily" or "economically" and controls the gearshift point accordingly. When controlling the gearshift process, the driving resistance is also taken into account, for example whether the car is moving uphill or downhill, braking acceleration and cornering.
Steptronic – automatic step-by-step switching
The 5-speed automatic transmission has a short step-by-step shift linkage next to the automatic shift track. Such shifts are common in motorsports.
With the Steptronic system, the driver can shift up or down as desired. Compared to manual shifting, the Steptronic system is significantly more comfortable and protected against operating errors. For example, a gear shift is not performed if the maximum permissible engine speed would be exceeded as a result.
If faults occur with the input signals or with the electromagnetic valves, the system switches to the emergency operating program. At the same time, faults that occur during operation are recorded in the fault memory. Refer to Section Troubleshooting. It is advisable to carry out the work in a service station.
To evaluate the operation of an automatic transmission and to find faults, a certain amount of experience is required. Therefore, only the removal of the transmission and the adjustment of the selector rod are described here. The oil in the transmission is changed only during repairs. Oil is not changed during maintenance.
Vehicles with AT are only permitted to be towed if the established rules are observed, please refer to Section Jacking and towing.