Gearshift System, Basic Function - GF27.60-D-1002A

Model All with transmission 725.0 

Overview 

This document contains information on:

• General 
• Function 
  • Shift operation
  • Upshift and downshift

General 

The gearshift system is responsible for changing between the various gears of the transmission.

Function 

Shift operation 

The fully integrated transmission controller unit converts the electrical signals coming from the fully integrated transmission control unit into hydraulic signals. Drive ranges "R", "N", "D1" to "D9", and "P" can be engaged by operating the DIRECT SELECT lever. Information on the engaged drive range "P", "R", "N", "D1" to "D9" is sent by the DIRECT SELECT lever to the fully integrated transmission control unit and the corresponding drive range is engaged.

The shift range for the engaged drive range "D1" to "D9" is displayed to the driver visually through equipment such as the instrument cluster. Although the shift range can be changed in the forward gears while driving, the fully integrated transmission control unit prevents a shift operation if the engine speeds are too high or too low.

Upshifts and downshifts 

In the Sport ("S") and Economy ("E") drive programs, the driver can select the following functions by pressing the steering wheel gearshift buttons:

• Pressing the steering wheel gearshift buttons in drive program "E" or "S" activates the short-term M program. This allows the driver to change gear using the steering wheel gearshift buttons without having to select the M program beforehand. The previous "gear limitation/shift into optimum gear" function is discontinued by using the steering wheel gearshift buttons.
• In contrast to the continuous M program, the short-term M program is deactivated automatically after a specific period. This time interval starts again after every additional press of a button. The activity of the function is extended depending on the wide open throttle and lateral acceleration involved.
• In drive program "E", in comparison to drive program "S", a shorter shift range (shifting at low engine speed) and therefore a lower drive torque is available when starting off forward and starting off in reverse. This allows for more economical and comfortable driving because the gears are not driven to the limit.
• In the "M" ("Manual") drive program, the individual gears "1" to "9" can be selected directly using the steering wheel gearshift buttons.

It is only possible to shift into the reverse gear and neutral using the DIRECT SELECT lever. The park pawl (gear range "P") is activated by operating the park pawl on the DIRECT SELECT lever.