automatic transmission MERCEDES-BENZ SPRINTER 2006 Repair Manual

Shift Phase - 1-2 Shift Phase 1
When the 1-2 and 4-5 shift solenoid valve (1) (Fig.
17) is turned on, the shift valve pressure (p-SV) is
directed onto the end face of the command valve (5).The command valve is moved and the shift pressure
(p-S) coming from the shift pressure shift valve (3) is
Fig. 17 Shift Phase - 1-2 Shift Phase 1
1 - 1-2/4-5 SHIFT SOLENOID 5 - 1-2/4-5 COMMAND VALVE
2 - 1-2/4-5 OVERLAP VALVE 6 - DRIVING CLUTCH K1
3 - 1-2/4-5 SHIFT PRESSURE SHIFT VALVE 7 - HOLDING CLUTCH B1
4 - 1-2/4-5 HOLDING PRESSURE SHIFT VALVE 8 - SHIFT PRESSURE REGULATOR VALVE
21 - 26 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

directed via the command valve (5) onto clutch K1
(6).
Simultaneously the clutch B1 (7) is subjected to
overlap pressure by the overlap regulating valve (2).
The pressure in the clutch B1 (7) as it disengages is
controlled during the shift phase depending on
engine load by the modulating pressure and the
applying clutch pressure (the shift pressure in clutch
K1). The controlled pressure in clutch B1 (7) is
inversely proportional to the capacity of the clutch
being engaged. The rising shift pressure (p-S) at
clutch K1 (6) acts on the annular face of the overlap
regulating valve (2) and reduces the overlap pressure
regulated by the overlap regulating valve (2). When a
corresponding pressure level is reached at the hold-
ing pressure shift valve (4), this valve switches over.
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 27

Shift Phase - 1-2 Shift Phase 2
The B1 (7) (Fig. 18) pressure acting on the end face
of the shift pressure shift valve (3) is replaced by the
working pressure (p-A). The shift pressure is alsorouted to the spring end of the holding valve (4) and
the holding valve downshifts. The line pressure is
then routed to the command valve (5).
Fig. 18 Shift Phase - 1-2 Shift Phase 2
1 - 1-2/4-5 SHIFT SOLENOID 5 - 1-2/4-5 COMMAND VALVE
2 - 1-2/4-5 OVERLAP VALVE 6 - DRIVING CLUTCH K1
3 - 1-2/4-5 SHIFT PRESSURE SHIFT VALVE 7 - HOLDING CLUTCH B1
4 - 1-2/4-5 HOLDING PRESSURE SHIFT VALVE 8 - SHIFT PRESSURE REGULATOR VALVE
21 - 28 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

Second Gear Engaged
After the gearchange is complete, the pressure on
the end face of the command valve (5) (Fig. 19) is
reduced via the 1-2 and 4-5 shift solenoid valve (1),and the command valve (5) is pushed back to its
basic position. Via the holding pressure shift valve
(4) the working pressure (p-A) now passes via the
Fig. 19 Second Gear Engaged
1 - 1-2/4-5 SHIFT SOLENOID 5 - 1-2/4-5 COMMAND VALVE
2 - 1-2/4-5 OVERLAP VALVE 6 - DRIVING CLUTCH K1
3 - 1-2/4-5 SHIFT PRESSURE SHIFT VALVE 7 - HOLDING CLUTCH B1
4 - 1-2/4-5 HOLDING PRESSURE SHIFT VALVE 8 - SHIFT PRESSURE REGULATOR VALVE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 29

command valve (5) to clutch K1 (6). The multiple-disc
holding clutch B1 (7) is deactivated (unpressurized).
The spring of the shift pressure shift valve (3) pushes
the valve back to its basic position.
21 - 30 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

Shift Phase - 2-1 Shift Phase 1
The 1-2/4-5 shift solenoid (1) (Fig. 20) is turned ON
to apply shift pressure (p-S) to the end face of the
1-2/4-5 command valve (5). This allows the commandvalve to up-shift and the shift pressure coming from
the 1-2/4-5 shift valve (3) is routed to the holding
clutch B1 (7) via the command valve.
Fig. 20 Shift Phase - 2-1 Shift Phase 1
1 - 1-2/4-5 SHIFT SOLENOID 5 - 1-2/4-5 COMMAND VALVE
2 - 1-2/4-5 OVERLAP VALVE 6 - DRIVING CLUTCH K1
3 - 1-2/4-5 SHIFT PRESSURE SHIFT VALVE 7 - HOLDING CLUTCH B1
4 - 1-2/4-5 HOLDING PRESSURE SHIFT VALVE 8 - SHIFT PRESSURE REGULATOR VALVE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 31

Simultaneously, the pressure in the releasing
clutch, K1 (6), is regulated at the 1-2/4-5 overlap
valve (2). The pressure in the K1 clutch as it disen-
gages is controlled during the shift phase depending
on engine load, via the modulating pressure
(p-MOD), and the shift pressure in clutch B1 (7). The
increasing shift pressure in clutch B1, which also
acts on the end face of the overlap valve, reduces the
overlap pressure.
21 - 32 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

Shift Phase - 2-1 Shift Phase 2
The pressure in clutch B1 (7) (Fig. 21) acting on
the end face of the 1-2/4-5 holding valve (4) forces the
valve to up-shift against the spring pressure andallows line pressure (p-A) to pass through the com-
mand valve (5).
Fig. 21 Shift Phase - 2-1 Shift Phase 2
1 - 1-2/4-5 SHIFT SOLENOID 5 - 1-2/4-5 COMMAND VALVE
2 - 1-2/4-5 OVERLAP VALVE 6 - DRIVING CLUTCH K1
3 - 1-2/4-5 SHIFT PRESSURE SHIFT VALVE 7 - HOLDING CLUTCH B1
4 - 1-2/4-5 HOLDING PRESSURE SHIFT VALVE 8 - SHIFT PRESSURE REGULATOR VALVE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 33

2-1 Shift - First Gear Engaged
After the gear change is complete, the 1-2/4-5 shift
solenoid (1) (Fig. 22) is turned off. This reduces the
pressure on the end face of the 1-2/4-5 commandvalve (5) to 0 psi and the spring pressure downshifts
the valve to its initial position. The line pressure
(p-A) is switched to the holding clutch B1 (7) and the
Fig. 22 First Gear Engaged
1 - 1-2/4-5 SHIFT SOLENOID 5 - 1-2/4-5 COMMAND VALVE
2 - 1-2/4-5 OVERLAP VALVE 6 - DRIVING CLUTCH K1
3 - 1-2/4-5 SHIFT PRESSURE SHIFT VALVE 7 - HOLDING CLUTCH B1
4 - 1-2/4-5 HOLDING PRESSURE SHIFT VALVE 8 - SHIFT PRESSURE REGULATOR VALVE
21 - 34 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

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.
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 35