Mercedes-Benz Sprinter / Dodge Sprinter. Manual — part 435

end face of the holding valve by the downshifted com-
mand valve. The upshifted holding valve also allows
the remaining pressure in clutch K1 (6) to be vented.

VA

AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

21 - 35

Gear Shift N to D (1st gear) - Engine Started

With the engine started (Fig. 23) and the gearshift

lever in the NEUTRAL or PARK positions, holding
clutch B1 (1) and driving clutch K3 (4) are applied
and the various valves in the 1-2/4-5 shift group are
positioned to apply pressure to the holding clutch B2.

Fig. 23 Engine Started

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 - 36

AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

VA

Activation Sequence

The selector valve (Fig. 24) opens the shift pres-

sure (p-S) feed connection from the ball valve (19)
with the shift valve B2 (9). With the shift valve B2
(9) in the upper position, shift pressure (p-S) travels
behind the piston B2 (5) and simultaneously to the
opposing face of the piston B2 (6). The multiple-disc
holding clutch B2 begins to close.

The pressure on the opposing face of the piston B2

(6) ensures a soft activation of the multiple-disc hold-
ing clutch B2.

Fig. 24 Activation Sequence

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

VA

AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

21 - 37

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 speci-
fied level, the TCM shuts off the power to the 3-4
shift solenoid valve (10) (Fig. 25). The spring cham-
ber 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 com-
mand 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 ener-
gized. 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 pres-
sure shift valve (12) and the 3-4 command valve (13)
to the piston of multiple-disc holding clutch B2 (5).

Fig. 25 First Gear Engaged

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 - 38

AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

VA