clutch MERCEDES-BENZ SPRINTER 2006 Service Manual

(2) Assemble piston guide (4) (Fig. 178) and B3
piston (8) in the correct position. Verify that the
missing tooth in the B3 piston/B2 outer disc carrier
(8) is aligned with the centerline of the two threaded
holes in the B2 and B3 piston guide (4).
(3) Insert B2 piston (10) (Fig. 178) in B3 piston
(8).
Fig. 178 Holding Clutch B2
1 - SNAP-RING 9 - B2 PISTON SEALING RING
2 - MULTIPLE DISC PACK 10 - B2 PISTON
3 - DISC SPRING 11 - PISTON GUIDE SEALING RING
4 - B2 AND B3 PISTON GUIDE 12 - PISTON GUIDE SEALING RING
5 - O-RING 13 - PISTON GUIDE RING
6 - B3 PISTON SEALING RING 14 - PISTON BACK PRESSURE DISC SPRING
7 - B3 PISTON SEALING RING 15 - SPRING PLATE
8 - B3 PISTON/B2 OUTER DISC CARRIER 16 - SNAP-RING
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 151

(4) Insert piston guide ring (2) (Fig. 179). The
valve (1) in the piston guide ring must be on top.
(5) Insert disc spring (14) (Fig. 178) 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. If the
original clutch discs are reused, be sure to return
the disc identified on disassembly as belonging on
top of the disc spring (3) to its original location.
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 by
mounting the Pressing Tool 8901 (1) (Fig. 180) on
outer multiple disc.
(11) Using a lever press, compress the pressing
tool as far as the stop (then the marking ring is still
visible, see small arrow).
Fig. 179 B2 Piston and Piston Guide Ring
1 - VALVE
2 - PISTON GUIDE RING
3 - B2 PISTON
Fig. 180 Measure B2 Clutch Clearance
1 - PRESSING TOOL 8901
2 - B3 PISTON/B2 OUTER DISC CARRIER
21 - 152 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

(12) Using a feeler gauge, determine the play ªLº
(Fig. 181) at three points between the snap-ring (8)
and outer multiple-disc (7).
(13) 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 ver-
sions.
(14) 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.).
INPUT SPEED SENSORS
DESCRIPTION
The input speed sensors (6, 8) (Fig. 182) are fixed
to the shell of the control unit via contact blades. The
speed sensors are pressed against the transmission
housing (2) by a spring (7) which is held against the
valve housing of the shift plate (5). This ensures a
defined distance between the speed sensors and the
exciter ring (4).
Fig. 181 B2 Clutch Stack-up
1 - B2 OUTER DISC CARRIER
2 - FRICTION DISCS
3 - DISC SPRING
4 - B2 PISTON
5 - OUTER MULTIPLE DISC - 1.8 MM (0.071 IN.)
6 - OUTER MULTIPLE DISC - 1.8 MM (0.071 IN.)
7 - OUTER MULTIPLE DISC - 6.5 MM (0.256 IN.)
8 - SNAP-RING
Fig. 182 Speed Sensors
1 - DRIVING CLUTCH K1
2 - TRANSMISSION HOUSING
3 - DRIVING CLUTCH K1 INTERNALLY TOOTHED DISC
4 - EXCITER RING
5 - VALVE HOUSING OF SHIFT PLATE
6 - N2 INPUT SPEED SENSOR
7 - SPRING
8 - N3 INPUT SPEED SENSOR
9 - EXCITER RING
10 - DRIVING CLUTCH K1 EXTERNALLY TOOTHED DISC
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 153

OPERATION
Signals from the input speed sensors (6, 8) (Fig.
183) are recorded in the transmission control module
(TCM) together with the wheel and engine speeds
and other information and are processed into an
input signal for electronic control.
Input speed sensor N2 (6) records the speed of the
front sun gear via the externally toothed disc carrier
of the multiple-disc clutch K1 (10) and input speed
sensor N3 (8) records the speed of the front planet
carrier via the internally toothed disc carrier of mul-
tiple-disc clutch K1 (3).
OIL PUMP
DESCRIPTION
The oil pump (2) (Fig. 184) (crescent-type pump) is
installed in the bellhousing behind the torque con-
verter and is driven by the drive flange of the torque
converter. The pump creates the oil pressure required
for the hydraulic procedures.
OPERATION
When the engine is running, the oil (Fig. 185) is
pumped through the inlet chamber (5) along the
Fig. 183 Input Speed Sensors
1 - DRIVING CLUTCH K1
2 - TRANSMISSION HOUSING
3 - DRIVING CLUTCH K1 INTERNALLY TOOTHED DISC
4 - EXCITER RING
5 - VALVE HOUSING OF SHIFT PLATE
6 - N2 INPUT SPEED SENSOR
7 - SPRING
8 - N3 INPUT SPEED SENSOR
9 - EXCITER RING
10 - DRIVING CLUTCH K1 EXTERNALLY TOOTHED DISC
Fig. 184 Oil Pump
1 - CRESCENT
2 - OIL PUMP
3 - EXTERNAL GEAR
4 - INTERNAL GEAR
5 - INLET CHAMBER
6 - PRESSURE CHAMBER
Fig. 185 Oil Pump
1 - CRESCENT
2 - OIL PUMP
3 - EXTERNAL GEAR
4 - INTERNAL GEAR
5 - INLET CHAMBER
6 - PRESSURE CHAMBER
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(9) Verify repair.
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
PRESSURE
Pressure (Fig. 213) 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. 214)
by applying a force to some given area in contact
with the fluid. A good example of this is a cylinderfilled 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, the
pressure in the fluid is the same everywhere within
the container.
FORCE MULTIPLICATION
Using the 10 PSI example used in the illustration
(Fig. 215), 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. 215), 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
Fig. 213 Force and Pressure Relationship
Fig. 214 Pressure on a Confined Fluid
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 163

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. 216) 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.
PLANETARY GEARTRAIN
DESCRIPTION
Three planetary gear sets (Fig. 217) are used to
produce the different gear ratios. These are located
in the mechanical part of the transmission as the
front, middle and rear planetary gear sets.
Fig. 215 Force Multiplication
Fig. 216 Piston Travel
Fig. 217 Planetary Geartrain
1 - ANNULUS GEAR
2 - PLANETARY PINION GEARS
3 - SUN GEAR
4 - PLANETARY CARRIER
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OPERATION
The annulus gear (1) (Fig. 218) and sun gear (3)
elements of a planetary gear system are alternately
driven and braked by the actuating elements of the
multi-plate clutch and multiple-disc brake. The plan-
etary pinion gears (2) can turn on the internal gear-
ing of the annulus gear (1) and on the external
gearing of the sun gear (3). This allows for a variety
of gear ratios and the reversal of the rotation direc-
tion without the need for moving gear wheels or shift
collars. When two components of the planetary gear
set are locked together, the planetary gear set is
locked and turns as a closed unit.
The torque and engine speed are converted accord-
ing to the lever ratios and the ratio of the number of
teeth on the driven gears to that on the drive gears,
and is referred to as the gear ratio. The overall ratio
of a number of planetary gear sets connected in
series is obtained by multiplying the partial ratios.
Fig. 218 Planetary Geartrain
1 - ANNULUS GEAR
2 - PLANETARY PINION GEARS
3 - SUN GEAR
4 - PLANETARY CARRIER
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 165

DISASSEMBLY
(1) Remove upper two visible Teflon rings (1) (Fig.
219) from output shaft.
(2) Remove retaining ring (11), shim (10), thrust
needle bearing (9) and thrust washer (8) from output
shaft.
(3) Remove clutch K3 (7).
(4) Remove rear tubular shaft/freewheeling clutch
F2 (6) (Fig. 219) from output shaft.
(5) Remove rear gear set (5) with integrated tubu-
lar shaft of center gear set from output shaft.
(6) Remove thrust washer (4).
Fig. 219 Output Shaft with Center and Rear Planetary Geartrain
1 - TEFLON RINGS 7 - DRIVING CLUTCH K3
2 - OUTPUT SHAFT WITH CENTER PLANETARY CARRIER 8 - THRUST WASHER
3 - NEEDLE BEARING 9 - AXIAL NEEDLE BEARING
4 - THRUST WASHER 10 - SHIM
5 - REAR PLANETARY GEAR SET 11 - RETAINING RING
6 - REAR HOLLOW SHAFT/FREEWHEELING CLUTCH F2
21 - 166 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

ASSEMBLY
(1) Mount thrust washer (4) (Fig. 220) with the
collar pointing towards the planet carrier.
(2) Mount the rear gear set (5) on the rear hollow
shaft (6).
(3) Using grease, install lower three Teflon rings
(1) (Fig. 220) in the groove so that the joint stays
together
(4) Put rear hollow shaft/freewheeling clutch F2
(6) with rear gear set (5) onto output shaft.
(5) Install clutch K3 (7).
(6) Mount retaining ring, shim, thrust needle bear-
ing and thrust washer (8 - 11) (Fig. 220).
(7) Using grease, insert the upper two Teflon rings
(1) in the groove so that the joint remains together.
Fig. 220 Output Shaft with Center and Rear Planetary Geartrain
1 - TEFLON RINGS 7 - DRIVING CLUTCH K3
2 - OUTPUT SHAFT WITH CENTER PLANETARY CARRIER 8 - THRUST WASHER
3 - NEEDLE BEARING 9 - AXIAL NEEDLE BEARING
4 - THRUST WASHER 10 - SHIM
5 - REAR PLANETARY GEAR SET 11 - RETAINING RING
6 - REAR HOLLOW SHAFT/FREEWHEELING CLUTCH F2
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 167

NOTE: During the test, apply a contact force by
hand to K3 in the direction of the arrow.
(8) Inspect axial play (Fig. 221) between shim (10)
and retaining ring (11). Check axial play ªSº between
shim (10) and retaining ring (1) using a feeler gauge.
Clearance should be 0.15-0.6 mm (0.006-0.024 in.).
Shims are available in thicknesses of 3.0 mm (0.118
in.), 3.4 mm (0.134 in.), and 3.7 mm (0.146 in.).
Adjust as necessary
SHIFT MECHANISM
DESCRIPTION
The automatic transmission is operated with the
help of a shift lever assembly (SLA) located in the
center console. There are four positions to which the
selection lever can be shifted: P, R, N, D. In addition,
the selector lever can be moved sideways (+/-) in posi-
tion ªDº to adjust the shift range.
All selector lever positions, as well as selected shift
ranges in position ªDº, are identified by the SLA. The
information is then sent to the transmission control
module (TCM) via a hardwire connection. At the
same time, the selector lever positions ªPº, ªRº, ªNº
and ªDº are transmitted by a shift cable to the selec-
tor shaft in the transmission.
The SLA is comprised of the following functions:²Key lock:Depending on the selector lever posi-
tion, the ignition lock is locked/unlocked, i.e., the
ignition key can be removed only if the selector lever
is in position ªPº. A park lock cable is used to per-
form this function.
²Park lock:The selector lever is not released
from postion ªPº until the brake pedal has been
applied and the ignition key is in driving position.
Shift lock is controlled by the brake light switch in
conjunction with a locking solenoid in the SLA. As
soon as the brake pedal is applied firmly, the locking
solenoid is retracted to unlock the selector lever. If
the selector lever cannot be moved out of position ªPº
due to a malfunction, the shift lock function can be
overriden (see operator's manual).
²Reverse inhibitor:As soon as the vehicle
speed exceeds approx. 4 mph, it is no longer possible
to move the selector lever from position ªNº to posi-
tion ªRº.
OPERATION
With the selector lever in position ªDº, the trans-
mission control module (TCM) automatically shifts
the gears that are best-suited to the current operat-
ing situation. This means that shifting of gears is
continuously adjusted to current driving and operat-
ing conditions in line with the selected shift range
and the accelerator pedal position. Starting off is
always performed in 1st gear.
The selector lever positions are determined by the
slider position of a potentiometer in the shift lever
assembly (SLA). The shift pattern diagram (position
display) and the program selector are illuminated by
the LEDs.
The current selector lever position or, if the shift
range has been limited, the current shift range is
indicated in the LCD display in the instrument clus-
ter.
The permissible shifter positions and transmission
operating ranges are:
²P = Parking lock and engine starting.
²R = Reverse.
²N = Neutral and engine starting (no power is
transmitted to the axles).
²D = The shift range includes all forward gears.
²4= Shift range is limited to gears 1 to 4.
²3= Shift range is limited to gears 1 to 3.
²2= Shift range is limited to gears 1 to 2.
²1= Shift range is limited to the 1st gear.
The shift range can be adjusted to the current
operating conditions by tipping the selector lever to
the left-hand side (ª-º) or the right-hand side (ª+º)
when in position ªDº. If the shift range is limited, the
display in the instrument cluster indicates the
selected shift range and not the currently engaged
gear.
Tipping the shift lever will have the following
results:Fig. 221 Check Center and Rear Planetary End-Play
1 - DRIVING CLUTCH K3
2 - THRUST WASHER
3 - SHIM
4 - AXIAL NEEDLE BEARING
5 - RETAINING RING
6 - OUTPUT SHAFT WITH CENTER PLANETARY CARRIER
21 - 168 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA