clutch MERCEDES-BENZ SPRINTER 2006 Service Manual

Torque Converter Lockup Clutch Regulating Valve
The torque converter lockup clutch regulating
valve (6) (Fig. 113) regulates the torque converter
lock-up clutch working pressure (p-TCC) in relation
to the torque converter clutch control pressure (p-S/
TCC). According to the size of the working pressure
(p-A), the torque converter lockup clutch is either
Engaged, Disengaged, or Slipping. When the regulat-
ing valve (6) is in the lower position, lubricating oil
flows through the torque converter and oil cooler (8)
into the transmission (torque converter lockup clutch
unpressurized). In its regulating position (slipping,
torque converter lockup clutch pressurized), a
reduced volume of lubricating oil flows through the
annular passage (7) bypassing the torque converter
and passing direct through the oil cooler into the
transmission. The rest of the lubricating oil is
directed via the throttle ªaº into the torque converter
in order to cool the torque converter lockup clutch.
Fig. 113 Torque Converter Lockup Clutch Regulating Valve
1 - TORQUE CONVERTER LOCK-UP CLUTCH
2 - TORQUE CONVERTER OUTPUT
3 - TORQUE CONVERTER INPUT
4 - LUBRICATION
5 - TORQUE CONVERTER LOCK-UP SOLENOID6 - TORQUE CONVERTER LOCK-UP CLUTCH REGULATING
VA LV E
7 - OIL COOLER
8 - LINE PRESSURE REGULATING VALVE
9 - OIL PUMP
21 - 114 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

Command Valve
When the end face is unpressurized (stationary
phase), the working pressure (p-A) is directed to the
actuated shift element. If the end face of the com-
mand valve (Fig. 115) is subjected to the shift valve
pressure (p-SV) (shift phase), then the shift pressure
(p-S) is switched to the activating element and the
overlap pressure (p-š) is switched to the deactivating
element.
Fig. 115 Command Valve
1 - HOLDING CLUTCH B1
2 - DRIVING CLUTCH K13 - 1-2/4-5 COMMAND VALVE
21 - 116 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

Shift Pressure Shift Valve
When the multiple-disc brake B1 (3) is activated,
the working pressure (p-A) is applied to the end face
of the 1-2 / 4-5 shift pressure shift valve (4) (Fig. 117)
via the command valve (1). Its shift state is main-
tained during the shift phase by substituting the
shift element pressure acting on its end face (and
which is variable during the shift phase) with a cor-
responding constant pressure. When the multi-plate
clutch K1 (2) is activated, the end face of the shift
valve is unpressurized during the stationary and
shift phases, so the shift state is maintained during
the shift phase in this case too.Lubrication Pressure Regulating Valve
At the working pressure regulating valve surplus
oil is diverted to the lubrication pressure regulating
valve (1) (Fig. 118), from where the lubrication pres-
sure (p-Sm) is used in regulated amounts to supply
the transmission lubrication system including the
torque converter.
Fig. 117 Shift Pressure Shift Valve
1 - 1-2/4-5 COMMAND VALVE
2 - DRIVING CLUTCH K13 - HOLDING CLUTCH B1
4 - 1-2/4-5 SHIFT PRESSURE SHIFT VALVE
Fig. 118 Lubrication Pressure Regulating Valve
1 - LUBRICATION PRESSURE REGULATING VALVE
21 - 118 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

Shift Pressure Regulating Valve
The shift pressure is determined by the shift pres-
sure regulating solenoid valve and the shift pressure
regulating valve (3) (Fig. 119). In addition, pressure
from the clutch K2 (1) is also present at the annular
surface (2) of the shift pressure regulating valve (3).
This reduces the shift pressure in 2nd gear.
Regulating Valve Pressure Regulating Valve
The regulating valve pressure (p-RV) is set at the
regulating valve pressure regulating valve (1) (Fig.
120) in relation to the working pressure (p-A) as far
as the maximum pressure.Shift Valve Pressure Regulating Valve
The non-constant regulating valve pressure (p-RV)
is regulated to a constant shift valve pressure (p-SV)
at the shift valve pressure regulating valve (1) (Fig.
121) and is used to supply the 1-2 and 4-5 / 3-4 / 2-3
solenoid valves and the torque converter lockup
clutch PWM solenoid valve.
Fig. 119 Shift Pressure Regulating Valve
1 - SHIFT PRESSURE REGULATING VALVE
Fig. 120 Regulating Valve Pressure Regulating
Valve
1 - REGULATING VALVE PRESSURE REGULATING VALVE
Fig. 121 Shift Valve Pressure Regulating Valve
1 - SHIFT VALVE PRESSURE REGULATING VALVE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 119

FLUID AND FILTER
DESCRIPTION
The oil level control (Fig. 147) is located on the
electrohydraulic unit (4) and consists of the float (5)
which is integrated into the electrohydraulic unit.
The float is positioned to plug the opening (6)
between the oil gallery (2) and gearset chamber (1) so
that the rotating gearsets do not splash about in oil
as the oil level rises. The oil level control reduces
power loss and prevents oil from being thrown out of
the transmission housing at high oil temperatures.
OPERATION
With low oil levels, the lubricating oil which flows
constantly out of the gearset, flows back to oil gallery
(2) though the opening (6). (Fig. 148) If the oil level
rises, the oil presses the float (5) against the housing
opening (6). The float (5) therefore separates the oil
gallery (2) from the gearset chamber (1). The lubri-
cating oil which continues to flow out of the gearsets
is thrown against the housing wall, incorporated by
the rotating parts and flows back into the oil gallery
(2) through the upper opening (arrow).
DIAGNOSIS AND TESTING
EFFECTS OF INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation, and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
Fig. 147 Fluid Level Control
1 - GEARSET CHAMBER
2 - OIL GALLERY
3 - SHELL OF ELECTROHYDRAULIC UNIT
4 - ELECTROHYDRAULIC UNIT
5 - FLOAT
6 - OPENING
Fig. 148 Fluid Level Control
1 - GEARSET CHAMBER
2 - OIL GALLERY
3 - SHELL OF ELECTROHYDRAULIC UNIT
4 - ELECTROHYDRAULIC UNIT
5 - FLOAT
6 - OPENING
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 131

CAUSES OF BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has three primary causes.
1. Internal clutch slippage, usually caused by low
line pressure, inadequate clutch apply pressure, or
clutch seal failure.
2. A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged oil cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
3. Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
FLUID CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failure
due to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The torque converter should be replaced whenever
a failure generates sludge and debris. This is neces-
sary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE
CHECK OIL LEVEL
(1) Verify that the vehicle is parked on a level sur-
face.
(2) Remove locking pin (1) (Fig. 149). Remove the
plate of the locking pin with a suitable tool and press
out the pin remaining in the cap downwards.
(3) Remove cap (2).
WARNING: Risk of accident from vehicle starting off
by itself when engine running. Risk of injury from
contusions and burns if you insert your hands into
the engine when it is started or when it is running.
Secure vehicle to prevent it from moving off by
itself. Wear properly fastened and close-fitting work
clothes. Do not touch hot or rotating parts.
(4) Actuate the service brake. Start engine and let
it run at idle speed in selector lever position ªPº.
(5) Shift through the transmission modes several
times with the vehicle stationary and the engine
idling
(6) Warm up the transmission, wait at least 2 min-
utes and check the oil level with the engine running.
Push the Oil Dipstick 8863A in up to the stop on the
electrohydraulic unit and pull out again, read off oil
level, repeat if necessary.
NOTE: The dipstick will protrude from the fill tube
approximately 75mm (3 inches) when installed.
Fig. 149 Remove Dipstick Tube Cap Lock
1 - LOCKING PIN
2 - TUBE CAP
3 - DIPSTICK TUBE
21 - 132 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

(14) Remove the transmission oil filter (1) and
o-ring from the electrohydraulic control unit.
(15) Clean the inside of the oil pan (3) of any
debris. Inspect the oil pan gasket (2) and replace if
necessary.
(16) Install a new oil filter (1) and o-ring into the
electrohydraulic control unit.
(17) Install the oil pan (3) and gasket (2) onto the
transmission.
(18) Install the oil pan bolts (5) and retainers (4).
Torque the bolts to 8 N´m (70 in.lbs.).
(19) Lower the vehicle and add 7.0 L (7.4 qts.) of
transmission fluid to the transmission.
(20) Check the oil level (Refer to 21 - TRANSMIS-
SION/AUTOMATIC - NAG1/FLUID AND FILTER -
STANDARD PROCEDURE - CHECK OIL LEVEL).
FREEWHEELING CLUTCH
DESCRIPTION
Freewheeling clutches (Fig. 154) are installed in
the front planetary gear set between the sun gear
and the stator shaft, and in the rear planetary gear
set between the sun gear and the intermediate shaft.
The freewheel consists of an outer race (4), an
inner race (7), a number of locking elements (3) and
a cage (6) for these locking elements.
OPERATION
The freewheeling clutch (Fig. 155) optimizes indi-
vidual gearshifts. They lock individual elements of a
planetary gear set together or against the transmis-
sion housing in one direction of rotation to allow the
torque to be transmitted.
If the inner race (7) of the freewheeling clutch is
locked and the outer race (4) turns counter-clockwise
(1), the locking elements (3) adopt a diagonal position
on account of their special contours, allowing the
freewheel function. The inner race (4) slides under
the locking elements (3) with minimal friction. If the
rotation of the outer race (4) changes to clockwise (2),
the locking elements (3) stand up and lock the outer
and inner races (4, 7) together.
Fig. 154 Freewheeling Clutch
1 - ROTATION DIRECTION ªA9
2 - ROTATION DIRECTION ªB9
3 - LOCKING ELEMENTS
4 - OUTER RACE
5 - FRONT OR REAR SUN GEAR
6 - LOCKING ELEMENT CAGE
7 - INNER RACE
Fig. 155 Freewheeling Clutch
1 - ROTATION DIRECTION ªA9
2 - ROTATION DIRECTION ªB9
3 - LOCKING ELEMENTS
4 - OUTER RACE
5 - FRONT OR REAR SUN GEAR
6 - LOCKING ELEMENT CAGE
7 - INNER RACE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 135

DISASSEMBLY
(1) Remove retaining ring (5) (Fig. 156) from hol-
low shaft (1).
(2) Remove rear sun gear (4) with the K3 inter-
nally toothed disk carrier and rear freewheeling
clutch F2 (3).
(3) Remove snap-ring (2) (Fig. 156) for freewheel.
(4) Press freewheeling clutch (3) out of sun gear.
(5) Check O-rings (6), replace if necessary.
Fig. 156 Freewheeling Clutch F2
1 - HOLLOW SHAFT 4 - K3 INNER DISC CARRIER AND REAR PLANETARY SUN
GEAR
2 - F2 CLUTCH SNAP-RING 5 - RETAINING RING
3 - FREEWHEELING CLUTCH F2 6 - O-RINGS
21 - 136 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

(6) Check the anti-friction bearing (2) (Fig. 157) in
the rear planetary sun gear for damage. Replace as
necessary.
Fig. 157 Freewheeling Clutch F2 Anti-Friction
Bearing
1 - K3 INNER DISC CARRIER AND REAR PLANETARY SUN
GEAR
2 - ANTI-FRICTION BEARING
3 - FREEWHEELING CLUTCH F2
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 137

ASSEMBLY
NOTE: The side of the freewheeling clutch F2 (3)
with the markings (directional arrow, part number,
etc.) must be up when the clutch is installed in the
sun gear (4).
(1) Press freewheeling clutch F2 (3) (Fig. 158) into
sun gear (4).
(2) Install snap-ring (2) for freewheeling clutch.
(3) Check O-rings (6) (Fig. 158) on hollow shaft,
replace if necessary.
(4) Install rear sun gear (4) with K3 internally
toothed disc carrier and rear freewheeling clutch (3)
onto the hollow shaft.
(5) Verify proper operation of the freewheeling
clutch F2. When the assembly is held with the F2clutch snap-ring upward, it should be possible to
rotate the hollow shaft counter-clockwise.
(6) Install retaining ring (5) onto hollow shaft (1).
GEARSHIFT CABLE
DIAGNOSIS AND TESTING
GEARSHIFT CABLE
(1) The floor shifter lever and gate positions
should be in alignment with all transmission PARK,
NEUTRAL, and gear detent positions.
(2) Engine starts must be possible with floor shift
lever in PARK or NEUTRAL gate positions only.
Fig. 158 Freewheeling Clutch F2
1 - HOLLOW SHAFT 4 - K3 INNER DISC CARRIER AND REAR PLANETARY SUN
GEAR
2 - F2 CLUTCH SNAP-RING 5 - RETAINING RING
3 - FREEWHEELING CLUTCH F2 6 - O-RINGS
21 - 138 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA