Engage gear range, function - GF27.60-P-3009AHX

TRANSMISSION 722.930 up to 31.5.11, 722.931 as of 1.6.11 in MODEL 212.0/2 

Function requirements for Engage gear range, general 

• Status "Circuit 87 ON"
• Circuit 61 ON

Engage gear range, general 

Each gear change is triggered by the fully integrated transmission control (VGS). In the process one component group is assigned to each shift operation. One component group consists of the respective control solenoid valve, the regulating valve involved, the responsible shift valve and the required multidisk brake or required multidisk clutch.

The pressure in the multidisk brake or multidisk clutch to be engaged is increased constantly while at the same time the pressure in the multidisk brake or multidisk clutch to be disengaged is reduced. This involves a flowing transition. Despite this the affected components are directly actuated and therefore enable shifting down through several gears.

Function sequence for engage gear range 

Shift operation N to D (1st gear) 

In position "N", multidisk brake B3 and multidisk clutch K3 are engaged. When the transmission is shifted from position "N" to position "D" at the DIRECT SELECT INTERFACE (N150), the feed to multidisk brake B2 is enabled by the selector valve. The fully integrated transmission control unit (Y3/8n4) actuates the multidisk brake control solenoid valve B2 (Y3/8y6) and the multidisk brake B2 is filled with oil.

The fully integrated transmission control unit uses the rpm difference (actual slip) between the engine speed and the transmission input speed to detect whether multidisk brake B2 is full. The control solenoid valve for multidisk brake actuation B2 actuates the regulating valve B2 or BR, which converts the adjacent working pressure into shift pressure and passes it on to the multidisk brake B2

In the fully integrated transmission control unit, the required slip (specified slip) is stored for the respective gear. The control pressure on regulating valve B2 or BR is changed via multidisk brake control solenoid valve B2 depending on this. The shift pressure produced by the regulating valve B2/BR depends on the geometry of the regulating valve B2/BR. The pressure in multidisk brake B2 is changed until the specified slip stored in the fully integrated transmission control unit is reached.