2005 MERCEDES-BENZ SPRINTER transmission fluid

ASSEMBLY
(1) Install piston (2) (Fig. 155) in outer multiple-
disc carrier (1). Press in piston using the disc spring
(3) and Multi-use Spring Compressor 8900 (8). Place
compressor (8) on disc spring (3) and compress until
the groove of the snap-ring is exposed
NOTE: Check vulcanized gasket, replace if neces-
sary.
(2) Insert snap-ring (4) (Fig. 155).
NOTE: The collar of the snap-ring must point
towards the multiple-disc pack. After installing,
check snap-ring for correct seat.
(3) Insert disc spring (5) and multiple-disc pack (6)
in the outer multiple-disc carrier.
(4) Insert snap-ring (7).NOTE: Pay attention to sequence of discs. Place
new friction multiple-discs in ATF fluid for one hour
before installing.
(5) Measure B1 clutch clearance.
(a) Mount Pressing Tool 8901 (1) (Fig. 156) on
outer multiple disc.
(b) Using a lever press (Fig. 156), compress
pressing tool as far as the stop (then the marking
ring is still visible, see small arrow).
(c) Using a feeler gauge, determine the play9L9
(Fig. 157) at three points between the snap-ring (6)
and outer multiple-disc (4). During the measure-
ment, the snap-ring (6) must contact the upper
bearing surface of the groove in the outer multiple-
disc carrier (5). The correct clearance is 2.3-2.7 mm
(0.091-0.106 in.) for 2 friction disc versions, 2.7-3.1
mm (0.106-0.122 in.) for 3 disc versions, and
3.0-3.4 mm (0.118-0.134 in.) for 4 disc versions.
Fig. 154 Holding Clutch B1
1 - HOLDING CLUTCH B1 OUTER CARRIER 5 - DISC SPRING
2 - PISTON 6 - MULTIPLE DISC PACK
3 - DISC SPRING 7 - SNAP-RING
4 - SNAP-RING 8 - MULTI-USE SPRING COMPRESSOR 8900
VAAUTOMATIC TRANSMISSION - NAG1 21 - 113
HOLDING CLUTCH B1 (Continued)

(8) Separate piston guide (4) from the B3 piston
(8) by blowing compressed air into the bore (A) (Fig.
159).
ASSEMBLY
(1) Assemble piston guide (4) (Fig. 160) and B3
piston (8) in the correct position.
(2) Check all sealing rings (Fig. 161), replace if
necessary. The rounded off edges on the sealing rings
(6), (3), and (2) must point outwards. The rounded off
edges on the sealing ring (4) must point inwards.
(3) Insert B2 piston (10) (Fig. 160) in B3 piston (8).
(4) Insert piston guide ring (2) (Fig. 162). The
valve (1) in the piston guide ring must be on top.
(5) Insert disc spring (14) (Fig. 160) and spring
plate (15). Insert disc spring with the curvature
towards the spring plate(6) Place Multi-use Spring Compressor 8900 on the
disc spring (14) and compress the spring until the
groove for the snap-ring is exposed.
(7) Insert snap-ring (16).
NOTE: Pay attention to sequence of discs. Place
new friction multiple-discs in ATF fluid for one hour
before installing.
(8) Insert disc spring (3) and multiple-disc pack (2)
in the B2 outer multiple-disc carrier.
(9) Insert snap-ring (1).
NOTE: During the measurement the snap-ring (8)
must contact the upper bearing surface of the
groove in the outer multiple-disc carrier.
(10) Measure the B2 clutch pack clearance.
(a) Mount Pressing Tool 8901 (1) (Fig. 163) on
outer multiple disc.
(b) Using a lever press, compress the pressing
tool as far as the stop (then the marking ring is
still visible, see small arrow).
(c) Using a feeler gauge, determine the play9L9
(Fig. 164) at three points between the snap-ring (8)
and outer multiple-disc (7).
(d) The correct clutch clearance is 1.9-2.3 mm
(0.075-0.091 in.) for the four friction disc versions
and 2.0-2.4 mm (0.079-0.095 in.) for the five disc
versions.
(e) Adjust with snap-ring (8), if necessary. Snap-
rings are available in thicknesses of 2.9 mm (0.114
in.), 3.2 mm (0.126 in.), 3.5 mm (0.138 in.), 3.8 mm
(0.150 in.), and 4.1 mm (0.162 in.).
Fig. 159 B2 Clutch Oil Supply Locations
A - B3 PISTON
B - B2 PISTON GUIDE RING SIDE
C - K3 CLUTCH FEED
D - B2 PISTON SHIFT SIDE
21 - 116 AUTOMATIC TRANSMISSION - NAG1VA
HOLDING CLUTCH B2 (Continued)

PISTONS
DESCRIPTION
There are several sizes and types of pistons used in
an automatic transmission. Some pistons are used to
apply clutches. They all have in common the fact
that they are round or circular in shape, located
within a smooth walled cylinder, which is closed at
one end and converts fluid pressure into mechanical
movement. The fluid pressure exerted on the piston
is contained within the system through the use of
piston rings or seals.
OPERATION
The principal which makes this operation possible
is known as Pascal's Law. Pascal's Law can be stated
as: ªPressure on a confined fluid is transmitted
equally in all directions and acts with equal force on
equal areas.º
Fig. 192 Engage Park Lock Cable to SLA
1 - PARK LOCK CABLE COUPLING
2 - LOCK TAB
3 - BOLT
4 - SHIFT LEVER ASSEMBLY (SLA)
5 - CONNECTOR
Fig. 193 Install Bottom Section Of Center
Instrument Panel
1 - SCREW
2 - BOTTOM CENTER PART OF INSTRUMENT PANEL
Fig. 194 Install Top Section Of Center Instrument
Panel
1 - SHIFT LEVER ASSEMBLY FRAME TRIM
2 - STORAGE COMPARTMENT
3 - TOP CENTER PART OF INSTRUMENT PANEL
4 - SCREW
5 - PLUG CONNECTIONS
6 - ASHTRAY
21 - 128 AUTOMATIC TRANSMISSION - NAG1VA
PARK LOCK CABLE (Continued)

PRESSURE
Pressure (Fig. 195) is nothing more than force
(lbs.) divided by area (in or ft.), or force per unit
area. Given a 100 lb. block and an area of 100 sq. in.
on the floor, the pressure exerted by the block is: 100
lbs. 100 in or 1 pound per square inch, or PSI as it is
commonly referred to.
PRESSURE ON A CONFINED FLUID
Pressure is exerted on a confined fluid (Fig. 196)
by applying a force to some given area in contact
with the fluid. A good example of this is a cylinder
filled with fluid and equipped with a piston that is
closely fitted to the cylinder wall. If a force is applied
to the piston, pressure will be developed in the fluid.
Of course, no pressure will be created if the fluid is
not confined. It will simply ªleakº past the piston.
There must be a resistance to flow in order to create
pressure. Piston sealing is extremely important in
hydraulic operation. Several kinds of seals are used
to accomplish this within a transmission. These
include but are not limited to O-rings, D-rings, lip
seals, sealing rings, or extremely close tolerances
between the piston and the cylinder wall. The force
exerted is downward (gravity), however, the principle
remains the same no matter which direction is taken.
The pressure created in the fluid is equal to the force
applied, divided by the piston area. If the force is 100
lbs., and the piston area is 10 sq. in., then the pres-
sure created equals 10 PSI. Another interpretation of
Pascal's Law is that regardless of container shape or
size, the pressure will be maintained throughout, as
long as the fluid is confined. In other words, thepressure in the fluid is the same everywhere within
the container.
FORCE MULTIPLICATION
Using the 10 PSI example used in the illustration
(Fig. 197), a force of 1000 lbs. can be moved with a
force of only 100 lbs. The secret of force multiplica-
tion in hydraulic systems is the total fluid contact
area employed. The illustration, (Fig. 197), shows an
area that is ten times larger than the original area.
The pressure created with the smaller 100 lb. input
is 10 PSI. The concept ªpressure is the same every-
whereº means that the pressure underneath the
larger piston is also 10 PSI. Pressure is equal to the
force applied divided by the contact area. Therefore,
by means of simple algebra, the output force may be
found. This concept is extremely important, as it is
also used in the design and operation of all shift
valves and limiting valves in the valve body, as well
as the pistons, of the transmission, which activate
the clutches and bands. It is nothing more than
using a difference of area to create a difference in
pressure to move an object.
PISTON TRAVEL
The relationship between hydraulic lever and a
mechanical lever is the same. With a mechanical
lever it's a weight-to-distance output rather than a
pressure-to-area output. Using the same forces and
areas as in the previous example, the smaller piston
(Fig. 198) has to move ten times the distance
required to move the larger piston one inch. There-
fore, for every inch the larger piston moves, the
smaller piston moves ten inches. This principle is
true in other instances also. A common garage floor
jack is a good example. To raise a car weighing 2000
lbs., an effort of only 100 lbs. may be required. For
every inch the car moves upward, the input piston at
the jack handle must move 20 inches downward.
Fig. 195 Force and Pressure Relationship
Fig. 196 Pressure on a Confined Fluid
VAAUTOMATIC TRANSMISSION - NAG1 21 - 129
PISTONS (Continued)

SHIFT PRESSURE CONTROL SOLENOID VALVE
The shift pressure control solenoid valve (1) (Fig.
214) is located in the shell of the electric valve con-
trol unit and pressed against the shift plate by a
spring.
Its purpose is to control the shift pressure depend-
ing on the continuously changing operating condi-
tions, such as load and gear change.
The shift pressure regulating solenoid valve (1) has
an interference fit and is sealed off to the valve body
of the shift plate (4) by a seal (arrow). The contact
springs (2) at the solenoid valve engage in a slot in
the conductor tracks (3). The force of the contact
springs (2) ensures secure contacts
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
Fig. 213 Torque Converter Lockup Clutch PWM
Solenoid Valve
1 - TORQUE CONVERTER LOCKUP CLUTCH PWM SOLENOID
VA LV E
2 - CONTACT SPRING
3 - CONDUCTOR TRACK
4 - VALVE HOUSING OF SHIFT PLATE
5 - O-RING
6 - CONDUCTOR TRACK
7 - CONTACT SPRING
Fig. 214 Shift Pressure Control Solenoid Valve
1 - SHIFT PRESSURE CONTROL SOLENOID VALVE
2 - CONTACT SPRING
3 - CONDUCTOR TRACK
4 - VALVE HOUSING SHIFT PLATE
5 - CONDUCTOR TRACK
6 - CONTACT SPRING
21 - 138 AUTOMATIC TRANSMISSION - NAG1VA
SOLENOID (Continued)

OPERATION - TRANSMISSION TEMPERATURE
SENSOR
The temperature of the transmission oil has a con-
siderable effect on the shifting time and therefore the
shift quality. By measuring the oil temperature, shift
operations can be optimized in all temperature
ranges. The transmission oil temperature sensor (1)
(Fig. 222) is switched in series with the park/neutral
contact. The temperature signal is transferred to the
TCM only when the dry-reed contact of the park/neu-
tral contact is closed in REVERSE or a forward gear
position.Refer to the Transmission Temperature Sensor
Specifications table (Fig. 223) for the relationship
between transmission temperature, sensor voltage,
and sensor resistance.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 224) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The con-
verter clutch engages in third gear. The torque con-
verter hub drives the transmission oil (fluid) pump.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid.
Fig. 220 Transmission Temperature Sensor
1 - TRANSMISSION TEMPERATURE SENSOR
Fig. 221 Park/Neutral Contact
1 - SHELL OF ELECTRIC CONTROL MODULE
2 - PLUNGER
3 - PERMANENT MAGNET
4 - DRY-REED CONTACT
Fig. 222 Transmission Temperature Sensor
1 - TRANSMISSION TEMPERATURE SENSOR
VAAUTOMATIC TRANSMISSION - NAG1 21 - 141
TEMPERATURE SENSOR/PARK-NEUTRAL CONTACT (Continued)

TORQUE CONVERTER CLUTCH (TCC)
The TCC (Fig. 229) was installed to improve the
efficiency of the torque converter that is lost to the
slippage of the fluid coupling. Although the fluid cou-
pling provides smooth, shock-free power transfer, it is
natural for all fluid couplings to slip. If the impeller
and turbine were mechanically locked together, a
zero slippage condition could be obtained. A hydraulic
piston with friction material was added to the tur-
bine assembly to provide this mechanical lock-up.
In order to reduce heat build-up in the transmis-
sion and buffer the powertrain against torsional
vibrations, the TCM can duty cycle the torque con-
verter lock-up solenoid to achieve a smooth applica-
tion of the torque converter clutch. This function,
referred to as Electronically Modulated Converter
Clutch (EMCC) can occur at various times depending
on the following variables:²Shift lever position
²Current gear range
²Transmission fluid temperature
²Engine coolant temperature
²Input speed
²Throttle angle
²Engine speed
OPERATION
The converter impeller (driving member), which is
integral to the converter housing and bolted to the
engine drive plate, rotates at engine speed. The con-
verter turbine (driven member), which reacts from
fluid pressure generated by the impeller, rotates and
turns the transmission input shaft.
Fig. 225 Impeller
1 - ENGINE FLEXPLATE 4 - ENGINE ROTATION
2 - OIL FLOW FROM IMPELLER SECTION INTO TURBINE
SECTION5 - ENGINE ROTATION
3 - IMPELLER VANES AND COVER ARE INTEGRAL
VAAUTOMATIC TRANSMISSION - NAG1 21 - 143
TORQUE CONVERTER (Continued)

TURBINE
As the fluid that was put into motion by the impel-
ler blades strikes the blades of the turbine, some of
the energy and rotational force is transferred into the
turbine and the input shaft. This causes both of them
(turbine and input shaft) to rotate in a clockwise
direction following the impeller. As the fluid is leav-
ing the trailing edges of the turbine's blades it con-
tinues in a ªhinderingº direction back toward the
impeller. If the fluid is not redirected before it strikes
the impeller, it will strike the impeller in such a
direction that it would tend to slow it down.
Fig. 226 Turbine
1 - TURBINE VANE 4 - PORTION OF TORQUE CONVERTER COVER
2 - ENGINE ROTATION 5 - ENGINE ROTATION
3 - INPUT SHAFT 6 - OIL FLOW WITHIN TURBINE SECTION
Fig. 227 Stator Components
1 - CAM (OUTER RACE)
2 - ROLLER
3 - SPRING
4 - INNER RACE
21 - 144 AUTOMATIC TRANSMISSION - NAG1VA
TORQUE CONVERTER (Continued)