2005 MERCEDES-BENZ SPRINTER Service Repair Manual

Wipe filler cap clean, then check the fluid level.
The dipstick should indicateCOLDwhen the fluid is
at normal temperature.
(1) Turn steering wheel all the way to the left
(2) Fill the pump fluid reservoir to the proper level
and let the fluid settle for at least two (2) minutes.
(3) Raise the front wheels off the ground.
(4)
Slowly turn the steering wheel lock-to-lock 20
times with the engine off while checking the fluid level.
NOTE: For vehicles with long return lines or oil
coolers turn wheel 40 times.
(5) Start the engine. With the engine idling main-
tain the fluid level.
(6) Lower the front wheels and let the engine idle
for two minutes.
(7) Turn the steering wheel in both direction and
verify power assist and quiet operation of the pump.
If the fluid is extremely foamy or milky looking,
allow the vehicle to stand a few minutes and repeat
the procedure.
CAUTION: Do not run a vehicle with foamy fluid for
an extended period. This may cause pump damage.
STANDARD PROCEDURE - FLUSHING POWER
STEERING SYSTEM
Flushing is required when the power steering/hy-
draulic booster system fluid has become contami-
nated. Contaminated fluid in the steering/booster
system can cause seal deterioration and affect steer-
ing gear/booster spool valve operation.
(1) Raise the front end of the vehicle off the
ground until the wheels are free to turn.
(2) Remove the return line from the pump.
NOTE: If vehicle is equipped with a hydraulic
booster remove both return lines from the pump.
(3) Plug the return line port/ports at the pump.
(4) Position the return line/lines into a large con-
tainer to catch the fluid.
(5) While an assistant is filling the pump reservoir
start the engine.
(6) With the engine running at idle turn the wheel
back and forth.
NOTE: Do not contact or hold the wheel against the
steering stops.
(7) Run a quart of fluid through the system then
stop the engine and install the return line/lines.
(8) Fill the system with fluid and perform Steering
Pump Initial Operation, (Refer to 19 - STEERING/
PUMP - STANDARD PROCEDURE).(9) Start the engine and run it for fifteen minutes
then stop the engine.
(10) Remove the return line/lines from the pump
and plug the pump port/ports.
(11) Pour fresh fluid into the reservoir and check
the draining fluid for contamination. If the fluid is
still contaminated, then flush the system again.
(12) Install the return line/lines and perform
Steering Pump Initial Operation, (Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
REMOVAL
(1) Remove the belt from the power steering pump.
(2) Siphon as much power steering fluid as possi-
ble out of the reservoir.
(3) Remove the high pressure power steering hose
at the pump (Fig. 1).
(4)
Remove the return hose from the pump (Fig. 1).
(5) Remove the bolts securing the power steering
pump to the engine (Fig. 1).
INSTALLATION
(1) Install the power steering pump to the engine
and tighten the bolts (Fig. 1). Tighten to 21 N´m (15
ft. lbs.).
(2) Replace all o-rings and hose clamps (Fig. 1).
(3) Install the return hose to the pump and tighten
the clamp (Fig. 1).
(4) Install the high pressure hose to the pump
(Fig. 1). Tighten to 38 N´m (28 ft. lbs.).
(5)
Fill the power steering fluid (Refer to 19 - STEER-
ING/PUMP/FLUID - STANDARD PROCEDURE).
Fig. 1 POWER STEERING PUMP
1 - PUMP MOUNTING BOLT
2 - CLAMP
3 - RETURN HOSE
4 - HIGH PRESSURE HOSE
5 - O-RING
6 - PUMP RESERVOIR
7 - PUMP
8 - PULLEY
9 - PULLEY BOLT
VAPUMP 19 - 13
PUMP (Continued)

SPECIFICATIONS - TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Power Steering Pump To
Timing Case Cover/
Support21 15 185
High Pressure Flexible
Hose To Power Steering
Pump38 28 336
Power Steering Pulley To
Pump30 22 265
FLUID
STANDARD PROCEDURE
POWER STEERING PUMP FILL AND BLEED
PROCEDURE
(1) Remove the cap from the fluid reservoir.
Check cap seal for damage and replace if
needed.
(2) Fill the power steering pump with Mopar
ATF+4 Automatic Transmission fluid or equivalent.
Do not fill fluid beyond the MAX mark.
(3) Raise the vehicles front wheels off the ground.
(4) With the engine off turn the steering wheel
from right to left.Perform this step until all the
bubble formations can no longer be seen in the
power steering reservoir.
(5) Start the engine and turn the steering wheel
with the engine at idle speed then shut the engine off
and check for correct oil level and no bubble in the
system.
(6) Reinstall power steering cap tightly.
(7) Test the system for leaks and proper operation.
FLUID COOLER TUBE
REMOVAL
(1) Siphon as much power steering fluid as possi-
ble out of the reservoir.
(2) Remove the grille (Refer to 23 - BODY/EXTE-
RIOR/GRILLE - REMOVAL).
(3) Remove the left headlight assembly.
(4) Disconnect the return lines from the cooler
tube.
(5) Remove the radiator clips (2).
(6) Remove the heat shield bolt for the turbo at
the core support.
(7) Remove the right headlight assembly.(8) Remove the core support bolts (4) and discon-
nect the hood latch cable.
(9) Remove the fan bracket bolts (4) to the radiator
(Fig. 2).
(10) Remove the two upper screws for the con-
denser (Fig. 2).
(11) Remove the condenser air dam shield.
(12) Remove the mounting screws for the cooler
tube (Fig. 2).
(13) Remove the cooler tube from the vehicle.
INSTALLATION
(1) Install the cooler tube to the vehicle.
(2) Install the cooler tube mounting screws (Fig.
2).
(3) Install the condenser air dam shield.
(4) Install the condenser upper mounting screws
(Fig. 2).
Fig. 2 FLUID COOLER TUBE
1 - MOUNTING SCREWS (4)
2 - FLUID COOLER
3 - ELECTRIC COOLING FAN
4 - A/C CONDENSOR
19 - 14 PUMPVA
PUMP (Continued)

(5) Install the fan bracket bolts to the radiator
(Fig. 2).
(6) Install the core support bolts and reconnect the
hood latch cable.
(7) Install the right headlight assembly.
(8) Install the bolt for the turbo shield at the core
support.
(9) Install the radiator clips.
(10) Install the return lines to the cooler tube.
(11) Install the left headlight assembly.
(12) Install the grille assembly (Refer to 23 -
BODY/EXTERIOR/GRILLE - INSTALLATION).
(13) Fill the power steering fluid (Refer to 19 -
STEERING/PUMP/FLUID - STANDARD PROCE-
DURE).
HOSES
REMOVAL
REMOVAL - PRESSURE HOSE
(1) Siphon as much power steering fluid as possi-
ble out of the reservoir.
(2) Disconnect the pressure hose at the pump.
(3) Disconnect the pressure hose at the steering
gear.
(4) Remove the pressure hose mounting bracket
from the gear.
(5) Remove the pressure hose from the vehicle.
REMOVAL - RETURN LINE FROM PUMP TO
COOLER TUBE
(1) Siphon as much power steering fluid as possi-
ble out of the reservoir.
(2) Disconnect the return line at the pump.
(3) Remove the grille (Refer to 23 - BODY/EXTE-
RIOR/GRILLE - REMOVAL).
(4) Remove the left headlight assembly.
(5) Disconnect the return line at the cooler tube.
(6) Remove the return line from the vehicle.
REMOVAL - RETURN HOSE FROM GEAR TO
COOLER TUBE
(1) Siphon as much power steering fluid as possi-
ble out of the reservoir.
(2) Disconnect the return hose from the gear.(3) Remove the grille (Refer to 23 - BODY/EXTE-
RIOR/GRILLE - REMOVAL).
(4) Remove the left headlight assembly.
(5) Disconnect the return line at the cooler tube.
(6) Remove the return line from the vehicle.
INSTALLATION
INSTALLATION - PRESSURE HOSE
(1) Install the pressure hose to the vehicle.
(2) Reconnect the pressure hose at the steering
gear. Tighten to 37 N´m (27 ft.lbs.).
(3) Install the pressure hose mounting bracket to
the steering gear.
(4) Reconnect the pressure hose at the power
steering pump. Tighten to 38 N´m (28 ft.lbs.).
(5) Fill the power steering fluid (Refer to 19 -
STEERING/PUMP/FLUID - STANDARD PROCE-
DURE).
INSTALLATION - RETURN LINE FROM PUMP
TO COOLER TUBE
(1) Install the return line to the vehicle.
(2) Reconnect the return line at the cooler tube.
(3) Install the left headlight assembly.
(4) Install the grille assembly (Refer to 23 - BODY/
EXTERIOR/GRILLE - INSTALLATION).
(5) Reconnect the return line at the power steering
pump.
(6) Fill the power steering fluid (Refer to 19 -
STEERING/PUMP/FLUID - STANDARD PROCE-
DURE).
INSTALLATION - RETURN HOSE FROM GEAR
TO COOLER TUBE
(1) Install the return line to the vehicle.
(2) Reconnect the return line at the cooler tube.
(3) Install the left headlight assembly.
(4) Install the grille assembly (Refer to 23 - BODY/
EXTERIOR/GRILLE - INSTALLATION).
(5) Reconnect the return line at the power steering
gear.
(6) Fill the power steering fluid (Refer to 19 -
STEERING/PUMP/FLUID - STANDARD
PROCEDURE).
VAPUMP 19 - 15
FLUID COOLER TUBE (Continued)

TRANSMISSION
AUTOMATIC TRANSMISSION - NAG1
TABLE OF CONTENTS
page page
AUTOMATIC TRANSMISSION - NAG1
DESCRIPTION..........................2
OPERATION............................4
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION......................23
DIAGNOSIS AND TESTING - PRELIMINARY . 23
DIAGNOSIS AND TESTING - ROAD
TESTING............................23
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION......................24
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR......................27
REMOVAL.............................27
DISASSEMBLY.........................30
ASSEMBLY............................34
INSTALLATION.........................41
SCHEMATICS AND DIAGRAMS............47
SPECIFICATIONS - NAG1 AUTOMATIC
TRANSMISSION......................68
SPECIAL TOOLS - NAG1 AUTOMATIC
TRANSMISSION......................69
DRIVING CLUTCHES
DESCRIPTION.........................72
OPERATION...........................72
DRIVING CLUTCH K1
DISASSEMBLY.........................74
ASSEMBLY............................75
DRIVING CLUTCH K2
DISASSEMBLY.........................76
ASSEMBLY............................78
DRIVING CLUTCH K3
DISASSEMBLY.........................80
ASSEMBLY............................80
ELECTROHYDRAULIC UNIT
DESCRIPTION.........................82
OPERATION...........................87
REMOVAL.............................92
DISASSEMBLY.........................92
ASSEMBLY............................95
INSTALLATION........................100
FLUID AND FILTER
DESCRIPTION........................101
OPERATION..........................101DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL.............102
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID.......................102
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION....................102
STANDARD PROCEDURE
STANDARD PROCEDURE - CHECK OIL
LEVEL.............................102
STANDARD PROCEDURE - TRANSMISSION
FILL...............................103
STANDARD PROCEDURE - FLUID/FILTER
SERVICE...........................104
FREEWHEELING CLUTCH
DESCRIPTION........................105
OPERATION..........................105
DISASSEMBLY........................106
ASSEMBLY...........................107
GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE.............................109
REMOVAL............................109
INSTALLATION........................109
HOLDING CLUTCHES
DESCRIPTION........................111
OPERATION..........................112
HOLDING CLUTCH B1
DISASSEMBLY........................112
ASSEMBLY...........................113
HOLDING CLUTCH B2
DISASSEMBLY........................115
ASSEMBLY...........................116
INPUT SPEED SENSORS
DESCRIPTION........................119
OPERATION..........................119
OIL PUMP
DESCRIPTION........................120
OPERATION..........................120
DISASSEMBLY........................120
ASSEMBLY...........................121
OUTPUT SHAFT BEARING
REMOVAL............................122
INSTALLATION........................122
VATRANSMISSION 21 - 1

OUTPUT SHAFT SEAL
REMOVAL............................125
INSTALLATION........................125
PARK LOCK CABLE
REMOVAL............................125
INSTALLATION........................126
PISTONS
DESCRIPTION........................128
OPERATION..........................128
PLANETARY GEARTRAIN
DESCRIPTION........................130
OPERATION..........................130
DISASSEMBLY........................131
ASSEMBLY...........................131
SHIFT MECHANISM
DESCRIPTION........................133
OPERATION..........................133
REMOVAL............................134
INSTALLATION........................135
SOLENOID
DESCRIPTION........................136OPERATION..........................138
TEMPERATURE SENSOR/PARK-NEUTRAL
CONTACT
DESCRIPTION
DESCRIPTION - PARK/NEUTRAL CONTACT . 139
DESCRIPTION - TRANSMISSION
TEMPERATURE SENSOR..............140
OPERATION
OPERATION - PARK/NEUTRAL CONTACT . . 140
OPERATION - TRANSMISSION
TEMPERATURE SENSOR..............141
TORQUE CONVERTER
DESCRIPTION........................141
OPERATION..........................143
REMOVAL............................146
INSTALLATION........................146
TORQUE CONVERTER HUB SEAL
REMOVAL............................147
INSTALLATION........................147
AUTOMATIC TRANSMISSION -
NAG1
DESCRIPTION
The NAG1 automatic transmission (Fig. 1) is an
electronically controlled 5-speed transmission with a
lock-up clutch in the torque converter. The ratios for
the gear stages are obtained by 3 planetary gear sets.
Fifth gear is designed as an overdrive with a high-
speed ratio.
The gears are actuated electronically/hydraulically.
The gears are shifted by means of an appropriate
combination of three multi-disc holding clutches,
three multi-disc driving clutches, and two freewheel-
ing clutches.
Electronic transmission control enables precise
adaptation of pressures to the respective operating
conditions and to the engine output during the shift
phase which results in a significant improvement in
shift quality.
Furthermore, it offers the advantage of a flexible
adaptation to various vehicle and engines.
Basically, the automatic transmission with elec-
tronic control offers the following advantages:
²Reduces fuel consumption.
²Improved shift comfort.
²More favourable step-up through the five gears.
²Increased service life and reliability.
²Lower maintenance costs.
TRANSMISSION IDENTIFICATION
The transmission name, NAG1, means New Auto-
matic Gearbox, generation 1.
The transmission can be generically identified
visually by the presence of a round 13-way connector
located near the front corner of the transmission oil
pan, on the right side. Specific transmission informa-
tion can be found stamped into a pad on the left side
of the transmission, above the oil pan rail.
TRANSMISSION GEAR RATIOS
The gear ratios for the NAG1 automatic transmis-
sion are as follows:
1st Gear.............................3.59:1
2nd Gear............................2.19:1
3rd Gear............................1.41:1
4th Gear............................1.00:1
5th Gear............................0.83:1
Reverse.............................3.16:1
TRANSMISSION HOUSING
The converter housing and transmission are made
from a light alloy. These are bolted together and cen-
tered via the outer multi-disc carrier of multi-disc
holding clutch, B1. A coated intermediate plate pro-
vides the sealing. The oil pump and the outer multi-
disc carrier of the multi-disc holding clutch, B1, are
bolted to the converter housing. The stator shaft is
pressed into it and prevented from rotating by
splines. The electrohydraulic unit is bolted to the
transmission housing from underneath. A sheet
metal steel oil pan forms the closure.
21 - 2 AUTOMATIC TRANSMISSION - NAG1VA

MECHANICAL SECTION
The mechanical section consists of a drive shaft,
output shaft, a sun gear shaft, and three planetary
gear sets which are coupled to each other. The plan-
etary gear sets each have four planetary pinion
gears. The oil pressure for the torque converter
lock-up clutch and clutch K2 is supplied through
bores in the drive shaft. The oil pressure to clutch K3
is transmitted through the output shaft. The lubri-
cating oil is distributed through additional bores in
both shafts. All the bearing points of the gear sets, as
well as the freewheeling clutches and actuators, are
supplied with lubricating oil. The parking lock gear
is connected to the output shaft via splines.
Freewheeling clutches F1 and F2 are used to opti-
mize the shifts. The front freewheel, F1, is supported
on the extension of the stator shaft on the transmis-
sion side and, in the locking direction, connects the
sun gear of the front planetary gear set to the trans-
mission housing. In the locking direction, the rear
freewheeling clutch, F2, connects the sun gear of thecenter planetary gear set to the sun gear of the rear
planetary gear set.
ELECTROHYDRAULIC CONTROL UNIT
The electrohydraulic control unit comprises the
shift plate made from light alloy for the hydraulic
control and an electrical control unit. The electrical
control unit comprises of a supporting body made of
plastic, into which the electrical components are
assembled. The supporting body is mounted on the
shift plate and screwed to it.
Strip conductors inserted into the supporting body
make the connection between the electrical compo-
nents and a plug connector. The connection to the
wiring harness on the vehicle and the transmission
control module (TCM) is produced via this 13-pin
plug connector with a bayonet lock.
Fig. 1 NAG1 Automatic Transmission
1 - TORQUE CONVERTER 11 - PARKING LOCK GEAR
2 - OIL PUMP 12 - INTERMEDIATE SHAFT
3 - DRIVESHAFT 13 - FREEWHEEL F2
4 - MULTI-DISC HOLDING CLUTCH B1 14 - REAR PLANETARY GEAR SET
5 - DRIVING CLUTCH K1 15 - CENTER PLANETARY GEAR SET
6 - DRIVING CLUTCH K2 16 - ELECTROHYDRAULIC CONTROL UNIT
7 - MULTI-DISC HOLDING CLUTCH B3 17 - FRONT PLANETARY GEAR SET
8 - DRIVING CLUTCH K3 18 - FREEWHEEL F1
9 - MULTI-DISC HOLDING CLUTCH B2 19 - STATOR SHAFT
10 - OUTPUT SHAFT 20 - TORQUE CONVERTER LOCK-UP CLUTCH
VAAUTOMATIC TRANSMISSION - NAG1 21 - 3
AUTOMATIC TRANSMISSION - NAG1 (Continued)

SHIFT GROUPS
The hydraulic control components (including actua-
tors) which are responsible for the pressure distribu-
tion before, during, and after a gear change are
described as a shift group. Each shift group contains
a command valve, a holding pressure shift valve, a
shift pressure shift valve, overlap regulating valve,
and a solenoid.
The hydraulic system contains three shift groups:
1-2/4-5, 2-3, and 3-4. Each shift group can also be
described as being in one of two possible states. The
active shift group is described as being in the shift
phase when it is actively engaging/disengaging a
clutch combination. The 1-2/4-5 shift group control
the B1 and K1 clutches. The 2-3 shift group controls
the K2 and K3 clutches. The 3-4 shift group controls
the K3 and B2 clutches.
OPERATION
The transmission control is divided into the elec-
tronic and hydraulic transmission control functions.
While the electronic transmission control is responsi-
ble for gear selection and for matching the pressures
to the torque to be transmitted, the transmission's
power supply control occurs via hydraulic elements
in the electrohydraulic control module. The oil supply
to the hydraulic elements, such as the hydrodynamic
torque converter, the shift elements and the hydrau-
lic transmission control, is provided by way of an oil
pump connected with the torque converter.
The Transmission Control Module (TCM) allows for
the precise adaptation of pressures to the correspond-
ing operating conditions and to the engine output
during the gearshift phase, resulting in a noticeable
improvement in shift quality. The engine speed limit
can be reached in the individual gears at full throttle
and kickdown. The shift range can be changed in the
forward gears while driving, but the TCM employs adownshift safeguard to prevent over-revving the
engine. The system offers the additional advantage of
flexible adaptation to different vehicle and engine
variants.
EMERGENCY RUNNING FUNCTION
In order to ensure a safe driving state and to pre-
vent damage to the automatic transmission, the TCM
control module switches to limp-home mode in the
event of critical faults. A DTC assigned to the fault is
stored in memory. All solenoid and regulating valves
are thus de-energized.
The net effect is:
²The last engaged gear remains engaged.
²The modulating pressure and shift pressures
rise to the maximum levels.
²The torque converter lockup clutch is deacti-
vated.
In order to preserve the operability of the vehicle
to some extent, the hydraulic control can be used to
engage 2nd gear or reverse using the following pro-
cedure:
²Stop the vehicle.
²Switch off engine.
²Move selector lever to9P9.
²Wait at least 10 seconds.
²Start engine.
²Move selector lever to D: 2nd gear.
²Move selector lever to R: Reverse gear.
The limp-home function remains active until the
DTC is rectified or the stored DTC is erased with the
DRBttool. Sporadic faults can be reset via ignition
OFF/ON.
CLUTCH APPLICATION
Refer to CLUTCH APPLICATION for which shift
elements are applied in each gear position.
CLUTCH APPLICATION
GEAR RATIO B1 B2 B3 K1 K2 K3 F1 F2
1 3.59 X* X X* X X
2 2.19 X X X* X
3 1.41 X X X
4 1.00 X X X
5 0.83 X X X X*
NX X
R 3.16 X* X X X
* = The shift components required during coast.
21 - 4 AUTOMATIC TRANSMISSION - NAG1VA
AUTOMATIC TRANSMISSION - NAG1 (Continued)