
CONDITION POSSIBLE CAUSES CORRECTION
HARD 3-2 DOWNSHIFT
WHEN DECELERATION
EVEN AFTER READAP-
TION1. K3 Idles. 1. Install TCM And/Or Electro-
hydraulic Control Unit.
NO RESP. DELAYED UP-
SHIFT, 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 AF-
TER FAST OFF (ACCEL-
ERATOR)1. Upshift Prevention To Realize Dy-
namical 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 Pow-
ered Vehicle Will Never Shift Into
5th Gear Below 250 km/h.1. Instruct Customer.
NO KICK DOWN SHIFT-
ING1. Accelerator Pedal Value < 95%. 1. Check Engine Control. Ad-
just 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 Nec-
essary.
2. Oil Filter Not Installed. 2. Install Oil Filter.
3. Free Wheeling Clutch F2 Defec-
tive.3. Replace Free Wheeling
Clutch F2, Hollow Shaft, and
Rear Sun Gear/Inner Disc Car-
rier K3.
GRABBING 2-3 COAST-
ING UPSHIFT AND/OR
BRAKE DOWNSHIFT1. Oil Level Too Low. 1. Check Oil Level. Add if Nec-
essary.
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.
DELAYED ENGAGEMENT,
NO TRANSFER OF POW-
ER IN R AND/OR D, ALSO
AT TIMES1. Oil Level Too Low. 1. Check Oil Level. Add if Nec-
essary.
2. Recognition Switch - Selector Le-
ver Position.2. Replace Recognition Switch
Only When Intermediate Posi-
tion 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 Proce-
dure (TCM, electrohydraulic
control unit or repair set).
5. Wrong Combination TCM/Electro-
hydraulic Control Unit.5. Check Combination TCM/
Electrohydraulic Control Unit.
Replace TCM Resp. Electrohy-
draulic Control Unit, if neces-
sary.
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 41

CONDITION POSSIBLE CAUSES CORRECTION
NO UPSHIFT OF 1ST
GEAR AT TIMES1. Connector Ballast Unit. Output
Speed Sensor Loose, Incorrectly
Contacted.1. Check Connectors, Replace
Output Speed sensor If Neces-
sary.
2. Output Speed Sensor Defective 2. Replace Output Speed Sen-
sor.
LEAKAGE AT THE AREA
OF THE ELECTRICAL
PLUG TO THE CONDUC-
TOR 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, Some-
times In The Control Module.4. Replace Conductor Plate.
LEAKAGE AT THE AREA
OF BELL HOUSING/
TORQUE CONVERTER1. Bolts (Torx M6) Outer Disc Carri-
er 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.
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 position ªNº.
(4) Remove oil drain plug (2) (Fig. 26) and drain
automatic transmission oil into a clean container.
21 - 42 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

installed. Retaining rings are available in thick-
nesses of 2.0 mm (0.079 in.), 2.1 mm (0.083 in.), and
2.2 mm (0.087 in.).
(31) Rotate the transmission so that the bellhous-
ing is pointed upward and ensuring that the output
shaft is allowed to move freely.
(32) Measure input shaft end-play (Fig. 58).
NOTE: If end-play is incorrect, transmission is
incorrectly assembled, or the geartrain end-play
shim is incorrect. The geartrain end-play shim is
selective.
(a) Attach Adapter 8266-18 (2) to Handle 8266-8
(1).
(b) Attach dial indicator C-3339 (3) to Handle
8266-8 (1).
(c) Install the assembled tool onto the input
shaft of the transmission and tighten the retaining
screw on Adapter 8266-18 to secure it to the input
shaft.
(d) Position the dial indicator plunger against a
flat spot on the oil pump and zero the dial indica-
tor.
(e) Move input shaft in and out and record read-
ing. End play should be 0.3-0.5 mm (0.012-0.020
in.). Adjust as necessary.(33) Install the output shaft washer onto the out-
put shaft.
(34) Install a new transmission rear seal into the
transmission case with Seal Installer 8902A (1) (Fig.
59).
(35) Place the transmission in PARK to prepare for
the installation of the output shaft nut.
(36) Install the propeller shaft flange onto the out-
put shaft and install an new flange nut. Tighten the
flange nut to 200 N´m (147.5 ft.lbs.).
(37) Place the Staking Tool 9078 (2) and Driver
Handle C-4171 onto the output shaft.
(38) Rotate the Staking Tool 9078 (2) until the
alignment pin (3) engages the output shaft notch (4)
(Fig. 60).
Fig. 58 Checking Input Shaft End Play
1 - TOOL 8266-8
2 - TOOL 8266-18
3 - TOOL C-3339
Fig. 59 Install Output Shaft Seal
1 - SEAL INSTALLER 8902A
2 - TRANSMISSION CASE
Fig. 60 Align Staking Tool 9078
1 - PROPELLER SHAFT FLANGE
2 - STAKING TOOL 9078
3 - ALIGNMENT PIN
4 - OUTPUT SHAFT NOTCH
21 - 58 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

(7) Detach oil pan (5) (Fig. 125).
(8) Remove oil filter (4).
(9) Unscrew Torx socket bolts (3) and remove elec-
trohydraulic control module (2).
DISASSEMBLY
(1) Remove electrohydraulic unit from the vehicle.
(Refer to 21 - TRANSMISSION/AUTOMATIC
TRANSMISSION - NAG1/ELECTROHYDRAULIC
UNIT - REMOVAL)
(2) Remove solenoid caps (1, 2) (Fig. 126).
(3) Unscrew Torxtsocket bolts (3, 4) (Fig. 126).
NOTE: Pay attention to the different lengths of the
TorxTsocket bolts.
(4) Remove leaf springs (5).
(5) Withdraw solenoid valves (6 - 11) from shift
plate (13).
NOTE: Check O-rings on solenoid valves for dam-
age and replace if necessary.
(6) Bend away retaining lug on stiffening rib on
transmission oil temperature sensor.
(7) Remove electrohydraulic control module (12)
from the shift plate (13).
Fig. 125 Remove Electrohydraulic Unit
1 - HEAT SHIELD
2 - ELECTROHYDRAULIC UNIT
3 - BOLT
4 - OIL FILTER
5 - OIL PAN
6 - CLAMPING ELEMENT
7 - BOLT
8 - DRAIN PLUG
9 - DRAIN PLUG GASKET
10 - 13-PIN PLUG CONNECTOR
11 - BOLT
12 - GUIDE BUSHINGFig. 126 Electrical Unit Components
1 - SOLENOID CAP
2 - SOLENOID CAP
3 - BOLT - M6X32
4 - BOLT - M6X30
5 - LEAF SPRING
6 - MODULATING PRESSURE REGULATING SOLENOID VALVE
7 - SHIFT PRESSURE REGULATING SOLENOID
8 - 3-4 SHIFT SOLENOID
9 - TORQUE CONVERTER LOCK-UP SOLENOID
10 - 1-2/4-5 SHIFT SOLENOID
11 - 2-3 SHIFT SOLENOID
12 - ELECTRICHYDRAULIC CONTROL MODULE
13 - SHIFT PLATE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 121

(13) Install the electrohydraulic control module
(12) onto the shift plate (13) (Fig. 142).
(14) Bend the retaining lug on stiffening rib on
transmission oil temperature sensor to retain the
electrohydraulic control module.
(15) Install the solenoid valves (6 - 11) into shift
plate (13).
NOTE: Check O-rings on solenoid valves for dam-
age and replace if necessary.
(16) Install the leaf springs (5).
(17) Install the Torxtsocket bolts (3, 4) (Fig. 142).
Tighten the bolts to 8 N´m (71 in.lbs.).
NOTE: Pay attention to the different lengths of the
TorxTsocket bolts.
(18) Install the solenoid caps (1, 2).
(19) Install the electrohydraulic unit into the vehi-
cle.
INSTALLATION
(1) Position the electrohydraulic unit in the trans-
mission housing.
(2) Insert selector valve (1) (Fig. 143) in driver of
detent plate (2). When installing the electrohydraulic
control module in the transmission housing, the plas-
tic part of the selector valve (1) must engage in the
driver of the detent plate (2).Fig. 142 Electrical Unit Components
1 - SOLENOID CAP
2 - SOLENOID CAP
3 - BOLT - M6X32
4 - BOLT - M6X30
5 - LEAF SPRING
6 - MODULATING PRESSURE REGULATING SOLENOID VALVE
7 - SHIFT PRESSURE REGULATING SOLENOID
8 - 3-4 SHIFT SOLENOID
9 - TORQUE CONVERTER LOCK-UP SOLENOID
10 - 1-2/4-5 SHIFT SOLENOID
11 - 2-3 SHIFT SOLENOID
12 - ELECTRICHYDRAULIC CONTROL MODULE
13 - SHIFT PLATE
Fig. 143 Connect The Selector Valve To The Detent
Plate
1 - SELECTOR VALVE
2 - DETENT PLATE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 129

(3) Install the Torxtsocket bolts (3) (Fig. 144) and
torque to 8 N´m (71 in.lbs.).
(4) Install a new oil filter (4) (Fig. 144).
(5) Install oil pan (5) (Fig. 144) and torque the oil
pan bolts to 8 N´m (71 in.lbs.).
(6) Install the oil drain plug (8) (Fig. 144) with a
new drain plug gasket (9). Torque the drain plug to
20 N´m (177 in.lbs.).
(7) Install the guide bushing (2) (Fig. 144) into the
transmission housing and install the bolt (11) to hold
the guide bushing in place.(8) Check O-ring on plug connector (1) (Fig. 145),
and replace if necessary.
(9) Install the plug connector (1) into the guide
bushing (2). Turn bayonet lock of guide bushing (2)
clockwise to connect plug connector (1).
(10) Position the heat shield (2) (Fig. 146) onto the
transmission housing and install the screw (1) and
bolt (3) to hold the shield in place.
(11) Fill the transmission with the correct oil
(Refer to LUBRICATION & MAINTENANCE/FLUID
TYPES - DESCRIPTION) using the standard proce-
dure (Refer to 21 - TRANSMISSION/AUTOMATIC -
NAG1/FLUID AND FILTER - STANDARD PROCE-
DURE - TRANSMISSION FILL).
Fig. 144 Install Electrohydraulic Unit
1 - HEAT SHIELD
2 - ELECTROHYDRAULIC UNIT
3 - BOLT
4 - OIL FILTER
5 - OIL PAN
6 - CLAMPING ELEMENT
7 - BOLT
8 - DRAIN PLUG
9 - DRAIN PLUG GASKET
10 - 13-PIN PLUG CONNECTOR
11 - BOLT
12 - GUIDE BUSHING
Fig. 145 Install Wiring Connector Plug
1 - PLUG CONNECTOR
2 - GUIDE BUSHING
Fig. 146 Install Heat Shield
1 - SCREW
2 - HEAT SHIELD
3 - BOLT
21 - 130 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA

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

(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. 150), 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. 151) and lock pin (1).
TRANSMISSION FILL
Fig. 150 NAG1 Transmission Fill Graph
Fig. 151 Dipstick Tube Cap Components
1 - LOCKING PIN
2 - TUBE CAP
3 - DIPSTICK TUBE
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 133