2005 MERCEDES-BENZ SPRINTER Service Repair Manual

FLUID AND FILTER
DESCRIPTION
The oil level control (Fig. 134) is located on the
electrohydraulic unit and consists of the float (5)
which is integrated into the electrohydraulic unit.
The float is positioned to plug the opening between
the oil gallery and gearset chamber so that the rotat-
ing 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 transmis-
sion housing at high oil temperatures.
OPERATION
With low oil levels (Fig. 135), the lubricating oil
which flows constantly out of the gearset, flows back
to oil gallery (2) though the opening (6). 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
lubricating oil which continues to flow out of the
gearsets is thrown against the housing wall, incorpo-
rated by the rotating parts and flows back into the
oil gallery (2) through the upper opening (arrow).
Fig. 133 Install Heat Shield
1 - SCREW
2 - HEAT SHIELD
3 - BOLT
Fig. 134 Fluid Level Control
1 - GEARSET CHAMBER
2 - OIL GALLERY
3 - SHELL OF ELECTROHYDRAULIC UNIT
4 - ELECTROHYDRAULIC UNIT
5 - FLOAT
6 - OPENING
Fig. 135 Fluid Level Control
1 - GEARSET CHAMBER
2 - OIL GALLERY
3 - SHELL OF ELECTROHYDRAULIC UNIT
4 - ELECTROHYDRAULIC UNIT
5 - FLOAT
6 - OPENING
VAAUTOMATIC TRANSMISSION - NAG1 21 - 101
ELECTROHYDRAULIC UNIT (Continued)

DIAGNOSIS AND TESTING
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.
DIAGNOSIS AND TESTING - 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 main 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.
DIAGNOSIS AND TESTING - 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 failuredue 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
STANDARD PROCEDURE - CHECK OIL LEVEL
(1) Verify that the vehicle is parked on a level sur-
face.
(2) Remove locking pin (1) (Fig. 136). 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.
Fig. 136 Remove Dipstick Tube Cap Lock
1 - LOCKING PIN
2 - TUBE CAP
3 - DIPSTICK TUBE
21 - 102 AUTOMATIC TRANSMISSION - NAG1VA
FLUID AND FILTER (Continued)

(4) Actuate the service brake. Start engine and let
it run at idle speed in selector lever position9P9.
(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.
(7) Check transmission oil temperature.
NOTE: The true transmission oil temperature can
only be read by a scan tool in REVERSE or any for-
ward gear position. (Refer to 21 - AUTOMATIC
TRANSMISSION- NAG1/TRANSMISSION TEMPERA-
TURE SENSOR/PARK-NEUTRAL SWITCH - OPERA-
TION)(8) The transmission Oil Dipstick 8863A has indi-
cator marks every 10mm. Determine the height of
the oil level on the dipstick and using the height, the
transmission temperature, and the Transmission
Fluid Graph (Fig. 137), determine if the transmission
oil level is correct.
(9) Add or remove oil as necessary and recheck the
oil level.
(10) Once the oil level is correct, install a new dip-
stick tube cap (2) (Fig. 138) and lock pin (1).
STANDARD PROCEDURE - TRANSMISSION
FILL
To avoid overfilling transmission after a fluid
change or overhaul, perform the following procedure:
(1) Verify that the vehicle is parked on a level sur-
face.
(2) Remove locking pin (1) (Fig. 139). 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).
(4) Add following initial quantity of Shellt3403 to
transmission:
Fig. 137 NAG1 Transmission Fill Graph
VAAUTOMATIC TRANSMISSION - NAG1 21 - 103
FLUID AND FILTER (Continued)

(a) If only fluid and filter were changed, add5.0
L (10.6 pts.)of transmission fluid to transmission.
(b) If transmission was completely overhauled,
torque converter was replaced or drained, and
cooler was flushed, add7.7 L (16.3 pts.)of trans-
mission fluid to transmission.
(5) Check the transmission fluid (Refer to 21 -
TRANSMISSION/AUTOMATIC - NAG1/FLUID -
STANDARD PROCEDURE) and adjust as required.
STANDARD PROCEDURE - FLUID/FILTER
SERVICE
(1) Run the engine until the transmission oil
reaches operating temperature.
(2) Raise and support vehicle.(3) Remove the torque converter drain plug access
plug from the bottom of the torque converter hous-
ing.
(4) Rotate the engine clockwise until the torque
converter drain plug (Fig. 140) is aligned with the
access hole.
NOTE: Clean the area around the drain plug to pre-
vent dirt from entering the torque converter.
(5) Using a suitable drain pan to catch the fluid,
remove the torque converter drain plug and allow the
torque converter to drain completely.
(6) Inspect the torque converter drain plug seal
(Fig. 140). Replace the seal if necessary.
(7) Install the torque converter drain plug. Tighten
the drain plug to 14 N´m (10 ft.lbs.).
(8) Install the torque converter drain plug access
plug into the bottom of the torque converter housing.
(9) Using a suitable drain pan to catch the fluid,
remove the transmission oil pan drain plug (Fig. 140)
and allow the oil pan to drain completely.
(10) Inspect the transmission oil pan drain plug
seal. Replace the seal if necessary.
(11) Install the transmission oil pan drain plug.
Tighten the drain plug to 20 N´m (15 ft.lbs.).
(12) Remove the bolts and retainers (Fig. 140)
holding the oil pan to the transmission.
(13) Remove the transmission oil pan and gasket
from the transmission.
Fig. 138 Dipstick Tube Cap Components
1 - LOCKING PIN
2 - TUBE CAP
3 - DIPSTICK TUBE
Fig. 139 Remove Dipstick Tube Cap Lock
1 - LOCKING PIN
2 - TUBE CAP
3 - DIPSTICK TUBE
Fig. 140 Fluid/Filter Service Points
1 - OIL FILTER
2 - OIL PAN GASKET
3 - OIL PAN
4 - RETAINER
5 - BOLT
6 - OIL PAN DRAIN PLUG
7 - SEAL
8 - TORQUE CONVERTER DRAIN PLUG
9 - SEAL
21 - 104 AUTOMATIC TRANSMISSION - NAG1VA
FLUID AND FILTER (Continued)

(14) Remove the transmission oil filter and o-ring
from the electrohydraulic control unit.
(15) Clean the inside of the oil pan of any debris.
Inspect the oil pan gasket and replace if necessary.
(16) Install a new oil filter and o-ring into the elec-
trohydraulic control unit.
(17) Install the oil pan and gasket onto the trans-
mission.
(18) Install the oil pan bolts and retainers. 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).
FREEWHEELING CLUTCH
DESCRIPTION
Freewheeling clutches (Fig. 141) 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. 142) 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 in direction9A9
(1), the locking elements (3) adopt a diagonal position
on account of their special contours, allowing the
freewheel function. The outer race (4) slides over the
locking elements (3) with negligible friction. If the
rotation of the outer race (4) changes to direction9B9
(2), the locking elements (3) stand up and lock the
outer and inner races (4, 7) together.
Fig. 141 Freewheeling Clutch
1 - ROTATION DIRECTION9A9
2 - ROTATION DIRECTION9B9
3 - LOCKING ELEMENTS
4 - OUTER RACE
5 - FRONT OR REAR SUN GEAR
6 - LOCKING ELEMENT CAGE
7 - INNER RACE
Fig. 142 Freewheeling Clutch
1 - ROTATION DIRECTION9A9
2 - ROTATION DIRECTION9B9
3 - LOCKING ELEMENTS
4 - OUTER RACE
5 - FRONT OR REAR SUN GEAR
6 - LOCKING ELEMENT CAGE
7 - INNER RACE
VAAUTOMATIC TRANSMISSION - NAG1 21 - 105
FLUID AND FILTER (Continued)

DISASSEMBLY
(1) Remove retaining ring (5) (Fig. 143) 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. 143) for freewheel.
(4) Press freewheeling clutch out of sun gear.
(5) Check O-rings (6), replace if necessary.
(6) Check the anti-friction bearing (Fig. 144) in the
rear planetary sun gear for damage. Replace as nec-
essary.
Fig. 143 Freewheeling Clutch F2
1 - HOLLOW SHAFT 4 - K3 INNER DISC CARRIER AND REAR PLANETARY SUN GEAR
2 - SNAP-RING 5 - RETAINING RING
3 - FREEWHEELING CLUTCH F2 6 - O-RINGS
21 - 106 AUTOMATIC TRANSMISSION - NAG1VA
FREEWHEELING CLUTCH (Continued)

ASSEMBLY
(1) Press freewheeling clutch F2 (3) (Fig. 145) into
sun gear (4).
(2) Install snap-ring (2) for freewheeling clutch.
(3) Check O-rings (6) (Fig. 145) 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) Install retaining ring (5) onto hollow shaft (1).
Fig. 144 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 21 - 107
FREEWHEELING CLUTCH (Continued)

Fig. 145 Freewheeling Clutch F2
1 - HOLLOW SHAFT 4 - K3 INNER DISC CARRIER AND REAR PLANETARY SUN GEAR
2 - SNAP-RING 5 - RETAINING RING
3 - FREEWHEELING CLUTCH F2 6 - O-RINGS
21 - 108 AUTOMATIC TRANSMISSION - NAG1VA
FREEWHEELING CLUTCH (Continued)