GM6 automatic gearbox

The GM6 automatic gearbox is a fully automatic 6-speed automatic gearbox for back-wheel / all-wheel drive with electronic control.

Brief description of components, GM6 automatic gearbox

Essentially, the GM6 automatic gearbox consists of the following components.

• Torque converter
  
• Converter housing
  
• Integrated oil pump
  
• 2 planetary gear sets
  
• Friction clutches and mechanical couplings
  
• Hydraulic pressure application and pressure control system with electronic control
  

Emergency running mode

There are two various types of emergency running mode:

Hydraulic emergency running mode

In the event of failure of an electrical component, the gearbox can switch into the hydraulic emergency running mode. In this case, all the solenoid valves are switched off and the gearbox shifts, if the 1st, 2nd or 3rd gear is engaged, permanently into 3rd gear. If the 4th, 5th or 6th gear is engaged in the event of failure of the electrical equipment, the gearbox shifts permanently into 5th gear. When the gearbox is operating in the emergency running mode, 5th gear is engaged and the ignition is switched of and on again, the gearbox shifts to 3rd gear.

Electrical emergency running mode

If a gripping clutch does not correctly engage or the releasing clutch does not correctly disengage, the gearbox control can switch into the emergency running mode. The gearbox works in the restricted mode. Defective clutches are not used. This means that only a limited number of gears is available

Gearbox adaptation

For gearbox adaptation, the following work must be carried out:

• Replacing the mechatronics
  
• Replacing the gearbox control
  
• Replacing the hydraulic selector unit
  
• Programming the gearbox control
  

After replacement of the entire gearbox, the service function does not have to be run, as the gearbox is already fully adapted on delivery.

The service function can be found at the following path:

Service functions/Drive/Gearbox control/Calibrations/Gearbox adaptation.