Automatic transmission overload protection, location/task/ function - GF27.00-P-7002A

TRANSMISSION 722 with ENGINE 104, 111 

Task 

To protect the shift elements of the automatic transmission against thermal overload during load shifts.

During load shifts (1-2-1, 2-3-2) the ignition angle is briefly adjusted towards "retarded" and thus the engine torque reduced when:

• the engine speed > 4000 rpm
• The air mass and throttle valve angle exceed set values
• Signal from transmission overload protection switch (S65) (load shifts 1-2-1, 2-3-2).

The transmission overload protection switch (S65) is a hydraulic pressure switch, connected in parallel with the brake band B1 and which closes at a pressure >1.8 bar.

Fig 1: Identifying Transmission Overload Protection Switch (S65)