2005 MERCEDES-BENZ SPRINTER Service Repair Manual

Activation Sequence
The selector valve (Fig. 18) opens the shift pres-
sure (p-S) feed connection from the ball valve (19)
with the shift valve B2 (9). With the shift valve B2
(9) in the upper position, shift pressure (p-S) travels
behind the piston B2 (5) and simultaneously to the
opposing face of the piston B2 (6). The multiple-disc
holding clutch B2 begins to close.The pressure on the opposing face of the piston B2
(6) ensures a soft activation of the multiple-disc hold-
ing clutch B2.
Fig. 18 Activation Sequence
1 - HOLDING CLUTCH B1 11 - PRESSURE HOLDING VALVE
2 - DRIVING CLUTCH K1 12 - 3-4 HOLDING PRESSURE SHIFT VALVE
3 - HOLDING CLUTCH B3 13 - 3-4 COMMAND VALVE
4 - DRIVING CLUTCH K3 14 - 3-4 SHIFT PRESSURE SHIFT VALVE
5 - HOLDING CLUTCH B2 PISTON 15 - 3-4 OVERLAP REGULATING VALVE
6 - HOLDING CLUTCH B2 PISTON OPPOSING FACE 16 - BALL VALVE
7 - SHIFT PRESSURE REGULATING SOLENOID 17 - 1-2/4-5 COMMAND VALVE
8 - SHIFT PRESSURE REGULATING VALVE 18 - 1-2/4-5 COMMAND VALVE
9 - SHIFT VALVE B2 19 - BALL VALVE
10 - 3-4 SHIFT SOLENOID
VAAUTOMATIC TRANSMISSION - NAG1 21 - 21
AUTOMATIC TRANSMISSION - NAG1 (Continued)

First Gear Engaged
The TCM monitors the activation sequence via the
speed of the input shaft, which slows down as the
frictional connection in the multiple-disc holding
clutch increases. When the speed drops to the speci-
fied level, the TCM shuts off the power to the 3-4
shift solenoid valve (10) (Fig. 19). The spring cham-
ber of the shift valve B2 (9) is depressurized and
switches downwards. This connects the line to the
opposing face of the piston B2 (6) with the pressure
holding valve (11). The pressure on the opposing face
of the piston B2 (6) drops to a residual pressure.
The working pressure (p-A) is formed and travels
via the 2-3 holding pressure shift valve, the 2-3 com-
mand valve and the ball valve (16) to multi-plate
clutch K3 (4) and via the 3-4 command valve (13) to
the end face of the 3-4 shift pressure shift valve (14).
The 3-4 shift pressure shift valve (14) is movedagainst the force of the spring towards the right. At
the same time the 3-4 solenoid valve (10) is ener-
gized. This allows shift valve pressure (p-SV) to enter
the spring chamber of the shift valve B2 (9) and to
reach the end face of the 3-4 command valve (13).
The shift valve B2 (9) is held in the upper position
and the 3-4 command valve (13) switches towards the
right. At the end face of the 3-4 shift pressure shift
valve (14) the working pressure (p-A) is replaced by
shift valve pressure (p-SV).
The 3-4 command valve (13) moves to the left.
Working pressure (p-A) travels via the holding pres-
sure shift valve (12) and the 3-4 command valve (13)
to the piston of multiple-disc holding clutch B2 (5).
Fig. 19 First Gear Engaged
1 - HOLDING CLUTCH B1 11 - PRESSURE HOLDING VALVE
2 - DRIVING CLUTCH K1 12 - 3-4 HOLDING PRESSURE SHIFT VALVE
3 - HOLDING CLUTCH B3 13 - 3-4 COMMAND VALVE
4 - DRIVING CLUTCH K3 14 - 3-4 SHIFT PRESSURE SHIFT VALVE
5 - HOLDING CLUTCH B2 PISTON 15 - 3-4 OVERLAP REGULATING VALVE
6 - HOLDING CLUTCH B2 PISTON OPPOSING FACE 16 - BALL VALVE
7 - SHIFT PRESSURE REGULATING SOLENOID 17 - 1-2/4-5 COMMAND VALVE
8 - SHIFT PRESSURE REGULATING VALVE 18 - 1-2/4-5 COMMAND VALVE
9 - SHIFT VALVE B2 19 - BALL VALVE
10 - 3-4 SHIFT SOLENOID
21 - 22 AUTOMATIC TRANSMISSION - NAG1VA
AUTOMATIC TRANSMISSION - NAG1 (Continued)

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION
CAUTION: Before attempting any repair on a NAG1
automatic transmission, check for Diagnostic Trou-
ble Codes with the DRBTscan tool.
Transmission malfunctions may be caused by these
general conditions:
²Poor engine performance.
²Improper adjustments.
²Hydraulic malfunctions.
²Mechanical malfunctions.
²Electronic malfunctions.
²Transfer case performance.
Diagnosis of these problems should always begin
by checking the easily accessible variables: fluid level
and condition, gearshift cable adjustment. Then per-
form a road test to determine if the problem has been
corrected or if more diagnosis is necessary.
DIAGNOSIS AND TESTING - PRELIMINARY
Two basic procedures are required. One procedure
for vehicles that are drivable and an alternate proce-
dure for disabled vehicles (will not back up or move
forward).
VEHICLE IS DRIVABLE
(1) Check for transmission fault codes using DRBt
scan tool.
(2) Check fluid level and condition.
(3) Adjust gearshift cable if complaint was based
on delayed, erratic, or harsh shifts.
(4) Road test and note how transmission upshifts,
downshifts, and engages.
VEHICLE IS DISABLED
(1) Check fluid level and condition.(2) Check for broken or disconnected gearshift
cable.
(3) Check for cracked, leaking cooler lines, or loose
or missing pressure-port plugs.
(4) Raise and support vehicle on safety stands,
start engine, shift transmission into gear, and note
following:
(a) If propeller shaft turns but wheels do not,
problem is with differential or axle shafts.
(b) If propeller shaft does not turn and transmis-
sion is noisy, stop engine. Remove oil pan, and
check for debris. If pan is clear, remove transmis-
sion and check for damaged driveplate, converter,
oil pump, or input shaft.
(c) If propeller shaft does not turn and transmis-
sion is not noisy, perform hydraulic-pressure test to
determine if problem is hydraulic or mechanical.
DIAGNOSIS AND TESTING - ROAD TESTING
Before road testing, be sure the fluid level and con-
trol cable adjustments have been checked and
adjusted if necessary. Verify that all diagnostic trou-
ble codes have been resolved.
Observe engine performance during the road test.
A poorly tuned engine will not allow accurate analy-
sis of transmission operation.
Operate the transmission in all gear ranges. Check
for shift variations and engine flare which indicates
slippage. Note if shifts are harsh, spongy, delayed,
early, or if part throttle downshifts are sensitive.
Slippage indicated by engine flare, usually means
clutch, overrunning clutch, or line pressure problems.
A slipping clutch can often be determined by com-
paring which internal units are applied in the vari-
ous gear ranges. The Clutch Application chart
CLUTCH APPLICATION provides a basis for analyz-
ing road test results.
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.
VAAUTOMATIC TRANSMISSION - NAG1 21 - 23
AUTOMATIC TRANSMISSION - NAG1 (Continued)

DIAGNOSIS AND TESTING - AUTOMATIC TRANSMISSION
CONDITION POSSIBLE CAUSES CORRECTION
MAXIMUM SPEED 30 km/h 1. Speed Control 30 Actuated. 1. Instruct Customer.
ENGINE DIES WHEN
TRANSMISSION IS
SHIFTED INTO GEAR,
ALSO NOISES IN N
AND/OR P1. PWM Valve Blocked. 1. Replace Valve.
2. Torque Converter Lock Up Control
Valve Locked.2. Enable Movement of Valve,
Remove Particle.
LEVER IN9P9POSITION
BLOCKED (BRAKE
ACTIVATED)1. No Vacuum Brake Booster After
Long Immobilization, Brake Pedal
Not Fully Applied/Hard Pedal.1. Check Vacuum/ Tightness of
Brake Booster.
2. No Stoplamp Switch Signal (no
DTC IN ECM).2. Check Contact to Stoplamp
Switch. Replace Switch if
Necessary.
GRUMBLING, DRONING,
JERKING WHEN TCC IS
ENGAGED1. Slip Speed TCC to Low. 1. Switch Off Torque Converter
Lock Up Using DRBT.If
Complaint Is Not Reproduced
Afterwards, Replace PWM
Valve, Set Adaption Values to
Zero.
HOWLING, HUMMING
ABOVE 4000 RPM IN
EACH GEAR1. Oil Filter Blocked. 1. Replace Oil Filter.
2. Oil Pump. 2. Replace Oil Pump.
WHINING, SINGING 1. Gear Set Noises in 1st, 2nd, 5th
Gear.1. Replace Transmission..
2. Intermediate Bearing Of The Drive
Shaft At 0 km/h, Only When Cold.2. Replace Intermediate
Bearing of the Drive Shaft.
9CLACK9NOISE FROM
CENTER SHIFT AREA
WHEN STOPPING OR
STARTING1. Park Lock Solenoid. 1. Replace Shift Lever
Assembly.
CRACKING NOISE WHEN
LOAD CYCLE1. Stick - Slip Between Joint Flange
and Collar Nut.1. Install Zinc Coated Collar Nut
Together With Washer.
CHATTERING IN CENTER
CONSOLE SHIFT WHILE
ACCELERATING1. Bushing Shift Shaft Has Too Much
Clearance.1. Replace Shifter Lever and
Cover Plate.
HARD 2-3 UPSHIFT WHEN
STEPPING OFF THE
ACCELERATOR PEDAL1. Response Characteristic Control
Loop.1. Install K2 Disc Spring.
UPSHIFT 2-3, 3-4
SLIPPING1. Spring of Regulating Valve
Pressure control Valve Broken.1. Replace Spring.
HARD 2-1 DOWNSHIFT
WHEN COMING TO A
STOP1. Transmission (2-1 downshift) Not
Adapted.1. Re-adapt Transmission.
2. TCM Software Data. 2. Flash TCM.
3. Free Wheeling Clutch F1
Defective.Replace Free Wheeling Clutch
F1.
21 - 24 AUTOMATIC TRANSMISSION - NAG1VA
AUTOMATIC TRANSMISSION - NAG1 (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
HARD 3-2 DOWNSHIFT
WHEN DECELERATION
EVEN AFTER
READAPTION1. K3 Idles. 1. Install TCM And/Or
Electrohydraulic Control Unit.
NO RESP. DELAYED
UPSHIFT, NO DTC1. Different Tire Sizes Are Mounted
On The Front Axle.1. Mount Uniform Tire Sizes On
The Front Axle.
NO UPSHIFT 3-4, 4-5
AFTER FAST OFF
(ACCELERATOR)1. Upshift Prevention To Realize
Dynamical Drivestyle.1. Instruct Customer.
NO UPSHIFT OF 1ST
GEAR BELOW 5000 RPM1. Gear Recognition Switch. 1. Replace Gear Recognition
Switch.
NO UPSHIFT INTO 5TH
GEAR WHEN FULL
THROTTLE OR KICK
DOWN ACTIVATION1. The Upshift 4-5 At Full Throttle or
Kick Down Never Occurs Until
Reaching Cut Off Speed. Under
These Conditions, The High
Powered Vehicle Will Never Shift
Into 5th Gear Below 250 km/h.1. Instruct Customer.
NO KICK DOWN
SHIFTING1. Accelerator Pedal Value < 95%. 1. Check Engine Control. Adjust
As Necessary.
Engine Turns Up While 2-3
Upshift and/or Hard 3-2
Downshift1. Oil Level Too Low. 1. Check Oil Level. Add if
Necessary.
2. Oil Filter Not Installed. 2. Install Oil Filter.
3. Free Wheeling Clutch F2
Defective.3. Replace Free Wheeling
Clutch F2, Hollow Shaft, and
Rear Sun Gear/Inner Disc
Carrier K3.
GRABBING 2-3 COASTING
UPSHIFT AND/OR BRAKE
DOWNSHIFT1. Oil Level Too Low. 1. Check Oil Level. Add if
Necessary.
2. Oil Filter Not Installed. 2. Install Oil Filter.
3. Control shift or Command Valve
Blocked.3. Check Each Slide Valve For
Base Position and Ease Of
Movement, Remove Particle.
4. K3 Disc Burnt, Hot Spots or
Rubbed Down.4. Replace Inner and Outer
Disc Carrier K3 And Control
Valve.
VAAUTOMATIC TRANSMISSION - NAG1 21 - 25
AUTOMATIC TRANSMISSION - NAG1 (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
DELAYED ENGAGEMENT,
NO TRANSFER OF
POWER IN R AND/OR D,
ALSO AT TIMES1. Oil Level Too Low. 1. Check Oil Level. Add if
Necessary.
2. Recognition Switch - Selector
Lever Position.2. Replace Recognition Switch
Only When Intermediate
Position or Fault is Indicated.
3. Oil Filter Not Installed. 3. Install Oil Filter.
4. AEV, Delayed Pressure Build Up
On Piston B2/B3.4. Install New Shifting
Procedure (TCM,
electrohydraulic control unit or
repair set).
5. Wrong Combination TCM/
Electrohydraulic Control Unit.5. Check Combination
TCM/Electrohydraulic Control
Unit. Replace TCM Resp.
Electrohydraulic Control Unit, if
necessary.
NO UPSHIFT OF 1ST
GEAR AT TIMES1. Connector Ballast Unit. Output
Speed Sensor Loose, Incorrectly
Contacted.1. Check Connectors, Replace
Output Speed sensor If
Necessary.
2. Output Speed Sensor Defective 2. Replace Output Speed
Sensor.
LEAKAGE AT THE AREA
OF THE ELECTRICAL
PLUG TO THE
CONDUCTOR PLATE1. Deformation O-Rings. 1. Replace O-Rings.
2. Deformation Adapter. 2.Replace Adaptor.
3. The Conductor Plate Is Not Fitted
Surface To Surface On The Valve
Body In One Corner, The Plug Is Not
Centered In The Socket And The
O-ring Will Not Seal.3. Remove Nose Of Conductor
Plate.
4. Contacting At The Conductor Plate
Leaky. Oil In Harness, Sometimes In
The Control Module.4. Replace Conductor Plate.
LEAKAGE AT THE AREA
OF BELL HOUSING/
TORQUE CONVERTER1. Bolts (Torx M6) Outer Disc Carrier
B1.1. Clean Thread and Install the
Bolts Using Sealer.
OIL LEAKS 1. 6 Lower Bolts (TorxM8) Converter
Housing.1. Clean Thread and Install the
Bolts Using Sealer.
2. Oil Drain Plug Converter Loose
Resp. No Seal Ring Installed.2. Install Drain Plug Correctly.
3. Weld Seam Of Torque Converter
Leaky.3. Replace Torque Converter.
4. Radial Sealing Ring Oil Pump
Defective.4. Replace Sealing Ring.
5. O-Ring Oil Pump Defective Or Not
Installed.5. Install O-Ring.
6. Bushing Of Oil Pump Loose,
caused By Missing Fit Bolt At
Transmission/Engine Flange.6. Install Fit Bolt If Necessary.
21 - 26 AUTOMATIC TRANSMISSION - NAG1VA
AUTOMATIC TRANSMISSION - NAG1 (Continued)

STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR
Damaged or worn threads in the aluminum trans-
mission case and valve body can be repaired by the
use of Heli-CoilsŸ, or equivalent. This repair con-
sists of drilling out the worn-out damaged threads.
Then tap the hole with a special Heli-CoilŸ tap, or
equivalent, and installing a Heli-CoilŸ insert, or
equivalent, into the hole. This brings the hole back to
its original thread size.
Heli-CoilŸ, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
REMOVAL
(1) Disconnect the negative (ground) battery cable.
CAUTION: Isolate ground lead to prevent accidental
contact.
(2) Apply parking brake.
(3) Move gear selector lever to position9N9.
(4) Remove oil drain plug (2) (Fig. 20) and drain
automatic transmission oil into a clean container.
(5) Remove oil filler pipe.
(a) Remove bolts (2) (Fig. 21) to cylinder head.
(b) Remove bolt (3) (Fig. 21) to transmission
flange and bolt (2) to transmission housing.
(c) Pull lower connection of oil filler pipe (1) (Fig.
21) out of the fill hole in the side of the transmis-
sion housing.
(d) Guide oil filler pipe (1) (Fig. 21) up and out.
(6) Remove exhaust heat shield (5) (Fig. 22).
(7) Remove retaining bracket (4) (Fig. 22).(8) Detach propeller shaft (1) (Fig. 22) at transmis-
sion (Refer to 3 - DIFFERENTIAL & DRIVELINE/
PROPELLER SHAFT/PROPELLER SHAFT -
REMOVAL). Move propeller shaft to the right and tie
up.
(9) Remove the cooler lines at transmission.
Fig. 20 Drain Transmission
1 - SEAL
2 - DRAIN PLUG
Fig. 21 Remove the Fill Tube
1 - FILL TUBE
2 - BOLTS TO CYLINDER HEAD AND TRANSMISSION HOUSING
3 - BOLT TO TRANSMISSION FLANGE
Fig. 22 Remove Propeller Shaft and Heat Shield
1 - PROPELLER SHAFT
2 - BOLT
3 - BOLT
4 - RETAINING BRACKET
5 - HEAT SHIELD
6 - WASHER
7 - BOLT
VAAUTOMATIC TRANSMISSION - NAG1 21 - 27
AUTOMATIC TRANSMISSION - NAG1 (Continued)

(a) Remove bracket for the oil cooler feed and
return lines (1) (Fig. 23) from engine oil pan
flange. Detail shows right side of motor. Position is
mirrored for the left side of engine.
(b) Detach bracket of cable retainer (4) (Fig. 24)
from the threaded shank of a engine oil pan bolt
(5).
(c) Press cable retainer (4) (Fig. 24) down and
out.
(d) Remove the bolts holding the oil cooler lines
(6) (Fig. 25) to the left and right sides of transmis-
sion and hang the lines to the side.
(10) Disconnect the transmission electrical connec-
tor (2) (Fig. 26) from transmission and hang to the
side. Turn sealing ring (3) counterclockwise and dis-
connect plug connection (2).
(11) Detach shift cable at transmission.(a) Unlatch ball socket latch (Fig. 27) of cable.
(b) Unclip shift cable retainer from retainer
bracket. When pulling out cable, press together
hooks of shift cable retainer at the points shown
(arrows).
(c) Pull shift cable out of ball socket. Ball socket
can remain on transmission lever.
(12) Remove the torque converter bolts.
(a) Remove the steering gear (1) (Fig. 28) from
the chassis crossmember.
(b) Lower the steering gear (1) (Fig. 28) down-
wards.
(c) Remove the plastic torque converter access
cover (1) (Fig. 29) at back of engine flange.
Fig. 23 Remove Cooler Line Supports
1 - COOLER LINES
Fig. 24 Remove Cable Support
1 - CABLE
2 - BOLT
Fig. 25 Remove Driver's Side Cooler Line
1 - COOLER LINE
Fig. 26 Remove Transmission Electrical Connector
and Cooler Line
1 - COOLER LINE
2 - TRANSMISSION ELECTRICAL CONNECTOR
3 - SEALING RING
21 - 28 AUTOMATIC TRANSMISSION - NAG1VA
AUTOMATIC TRANSMISSION - NAG1 (Continued)