First Gear Engaged
The TCM monitors the activation sequence via the speed of the input shaft, which slows down as the frictional
connection in the multiple-disc holding clutch increases. When the speed drops to the specified level, the TCM shuts
off the power to the 3-4 shift solenoid valve (10). The spring chamber of the shift valve B2 (9) is depressurized and
switches downwards. This connects the line to the opposing face of the piston B2 (6) with the pressure holding
valve (11). The pressure on the opposing face of the piston B2 (6) drops to a residual pressure.
The working pressure (p-A) is formed and travels via the 2-3 holding pressure shift valve, the 2-3 command valve
and the ball valve (16) to multi-plate clutch K3 (4) and via the 3-4 command valve (13) to the end face of the 3-4
shift pressure shift valve (14). The 3-4 shift pressure shift valve (14) is moved against the force of the spring
towards the right. At the same time the 3-4 solenoid valve (10) is energized. This allows shift valve pressure (p-SV)
to enter the spring chamber of the shift valve B2 (9) and to reach the end face of the 3-4 command valve (13). The
shift valve B2 (9) is held in the upper position and the 3-4 command valve (13) switches towards the right. At the
end face of the 3-4 shift pressure shift valve (14) the working pressure (p-A) is replaced by shift valve pressure
(p-SV).
The 3-4 command valve (13) moves to the left. Working pressure (p-A) travels via the holding pressure shift valve
(12) and the 3-4 command valve (13) to the piston of multiple-disc holding clutch B2 (5).
1 - HOLDING CLUTCH B1
11 - PRESSURE HOLDING VALVE
2 - DRIVING CLUTCH K1
12 - 3-4 HOLDING PRESSURE SHIFT VALVE
3 - HOLDING CLUTCH B3
13 - 3-4 COMMAND VALVE
4 - DRIVING CLUTCH K3
14 - 3-4 SHIFT PRESSURE SHIFT VALVE
5 - HOLDING CLUTCH B2 PISTON
15 - 3-4 OVERLAP REGULATING VALVE
6 - HOLDING CLUTCH B2 PISTON OPPOSING FACE
16 - BALL VALVE
7 - SHIFT PRESSURE REGULATING SOLENOID
17 - 1-2/4-5 COMMAND VALVE
8 - SHIFT PRESSURE REGULATING VALVE
18 - 1-2/4-5 COMMAND VALVE
9 - SHIFT VALVE B2
19 - BALL VALVE
10 - 3-4 SHIFT SOLENOID
21 - 718
AUTOMATIC TRANSMISSION - NAG1 - SERVICE INFORMATION
WK