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
²Tipping the selector lever toward ª-º one
time after another:The shift range is reduced in
descending sequence by one gear each time, i.e., from
D-4-3-2-1.Iftheselected limitation of the shift
range would result in a downshift causing excessive
engine speed, the shifting is not executed and the
engaged gear as well as the shift range remain
unchanged. This is to prevent the engine from over-
speeding. Engine retardation is low with the selector
lever in position ªDº. To make use of the full braking
power of the engine, ªmanualº downshifting by tip-
ping the lever towards the left-hand side is recom-
mended. If this has been done, subsequent upshifting
must be carried out manually as well.
²Tipping the selector lever toward ª-º and
holding it in this position:The currently engaged
gear in range ªDº is indicated in the instrument clus-
ter display and the shift range is limited to this gear.
²Tipping the selector lever toward ª+º one
time after another:The shift range is increased by
one gear each time and the increased shift range is
displayed in the instrument cluster; possibly, the
transmission upshifts to a faster gear.
²Tipping the selector lever toward ª+º sev-
eral times:The shift range is increased by one gear
each time the lever is tipped until the shift range
ends up in ªDº.
²Tipping the selector lever toward ª+º and
holding it in this position:The shift range is
extended immediately to ªDº, shift ranges are indi-
cated in ascending sequence; possibly, the transmis-
sion upshifts to a faster gear due to the extension of
the shift range.
REMOVAL
(1) Move selector lever to position ªDº.
(2) Remove top section (3) (Fig. 222) of the center
section of instrument panel.
(3) Remove bottom section (2) (Fig. 223) of the cen-
ter section of instrument panel.
Fig. 222 Remove Top Section Of Center Instrument
Panel
1 - SHIFT LEVER ASSEMBLY FRAME TRIM
2 - STORAGE COMPARTMENT
3 - TOP CENTER PART OF INSTRUMENT PANEL
4 - SCREW
5 - PLUG CONNECTIONS
6 - ASHTRAY
Fig. 223 Remove Bottom Section Of Center
Instrument Panel
1 - SCREW
2 - BOTTOM CENTER PART OF INSTRUMENT PANEL
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 169
Refer to the Transmission Temperature Sensor
Specifications table (Fig. 241) for the relationship
between transmission temperature, sensor voltage,
and sensor resistance.
TORQUE CONVERTER
DESCRIPTION
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid.
The torque converter (Fig. 242) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine (1), a stator (3),
an overrunning clutch, an impeller (2), and an elec-
tronically applied converter clutch. The converter
clutch provides reduced engine speed and greater
fuel economy when engaged. Clutch engagement also
provides reduced transmission fluid temperatures.
The converter clutch engages in third through fifth
gears. The torque converter hub drives the transmis-
sion oil (fluid) pump.
A turbine damper (6) has been added for some
applications to help improve vehicle noise, vibration,
and harshness (NVH) characteristics.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
Fig. 241 Transmission Temperature Sensor
Specifications
Fig. 242 Torque Converter
1 - TURBINE
2 - IMPELLER
3-STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
6 - TURBINE DAMPER
21 - 178 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA
IMPELLER
The impeller (3) (Fig. 243) is an integral part of
the converter housing. The impeller consists of
curved blades placed radially along the inside of the
housing on the transmission side of the converter. As
the converter housing is rotated by the engine, so is
the impeller, because they are one and the same and
are the driving members of the system.
Fig. 243 Impeller
1 - ENGINE FLEXPLATE 4 - ENGINE ROTATION
2 - OIL FLOW FROM IMPELLER SECTION INTO TURBINE SEC-
TION5 - ENGINE ROTATION
3 - IMPELLER VANES AND COVER ARE INTEGRAL
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 179
TURBINE
The turbine (1) (Fig. 244) is the output, or driven,
member of the converter. The turbine is mounted
within the housing opposite the impeller, but is not
attached to the housing. The input shaft is inserted
through the center of the impeller and splined into
the turbine. The design of the turbine is similar to
the impeller, except the blades of the turbine are
curved in the opposite direction.
Fig. 244 Turbine
1 - TURBINE VANE 4 - PORTION OF TORQUE CONVERTER COVER
2 - ENGINE ROTATION 5 - ENGINE ROTATION
3 - INPUT SHAFT 6 - OIL FLOW WITHIN TURBINE SECTION
21 - 180 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA
²Transmission fluid temperature
²Engine coolant temperature
²Input speed
²Throttle angle
²Engine speed
OPERATION
The converter impeller (driving member) (2) (Fig.
248), which is integral to the converter housing and
bolted to the engine drive plate, rotates at engine
speed. The converter turbine (driven member) (1),
which reacts from fluid pressure generated by the
impeller, rotates and turns the transmission input
shaft (4).
TURBINE
As the fluid that was put into motion by the impel-
ler blades strikes the blades of the turbine, some of
the energy and rotational force is transferred into the
turbine and the input shaft. This causes both of them
(turbine and input shaft) to rotate in a clockwise
direction following the impeller. As the fluid is leav-
ing the trailing edges of the turbine's blades it con-
tinues in a ªhinderingº direction back toward the
impeller. If the fluid is not redirected before it strikes
the impeller, it will strike the impeller in such a
direction that it would tend to slow it down.
STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft. (Fig. 249)
Under stall conditions (the turbine is stationary), the
oil leaving the turbine blades strikes the face of the
stator blades and tries to rotate them in a counter-
clockwise direction. When this happens the over-run-
ning clutch of the stator locks and holds the stator
from rotating. With the stator locked, the oil strikes
the stator blades and is redirected into a ªhelpingº
direction before it enters the impeller. This circula-
tion of oil from impeller to turbine, turbine to stator,
and stator to impeller, can produce a maximum
torque multiplication of about 2.0:1. As the turbine
begins to match the speed of the impeller, the fluid
that was hitting the stator in such as way as to
cause it to lock-up is no longer doing so. In this con-
dition of operation, the stator begins to free wheel
and the converter acts as a fluid coupling.
Fig. 248 Torque Converter
1 - TURBINE
2 - IMPELLER
3-STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
6 - TURBINE DAMPER
Fig. 249 Stator Operation
1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL
PUSHING ON BACKSIDE OF VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING
AGAINST STATOR VANES
21 - 182 AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATIONVA
TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller (2)
and turbine (1) are rotating at about the same speed
and the stator (3) is freewheeling, providing no
torque multiplication. By applying the turbine's pis-
ton and friction material (9) (Fig. 250), a total con-
verter engagement can be obtained. The result of this
engagement is a direct 1:1 mechanical link between
the engine and the transmission.
The clutch can be engaged in second, third, fourth,
and fifth gear ranges.
The TCM controls the torque converter by way of
internal logic software. The programming of the soft-
ware provides the TCM with control over the torque
converter solenoid. There are four output logic states
that can be applied as follows:
²No EMCC
²Partial EMCC
²Full EMCC
²Gradual-to-no EMCC
NO EMCC
Under No EMCC conditions, the TCC Solenoid is
OFF. There are several conditions that can result inNO EMCC operations. No EMCC can be initiated
due to a fault in the transmission or because the
TCM does not see the need for EMCC under current
driving conditions.
PARTIAL EMCC
Partial EMCC operation modulates the TCC Sole-
noid (duty cycle) to obtain partial torque converter
clutch application. Partial EMCC operation is main-
tained until Full EMCC is called for and actuated.
During Partial EMCC some slip does occur. Partial
EMCC will usually occur at low speeds, low load and
light throttle situations.
FULL EMCC
During Full EMCC operation, the TCM increases
the TCC Solenoid duty cycle to full ON after Partial
EMCC control brings the engine speed within the
desired slip range of transmission input speed rela-
tive to engine rpm.
GRADUAL - TO - NO EMCC
This operation is to soften the change from Full or
Partial EMCC to No EMCC. This is done at mid-
throttle by decreasing the TCC Solenoid duty cycle.
REMOVAL
(1) Remove transmission and torque converter
from vehicle.
(2) Place a suitable drain pan under the converter
housing end of the transmission.
CAUTION: Verify that transmission is secure on the
lifting device or work surface, the center of gravity
of the transmission will shift when the torque con-
verter is removed creating an unstable condition.
The torque converter is a heavy unit. Use caution
when separating the torque converter from the
transmission.
(3) Pull the torque converter forward until the cen-
ter hub clears the oil pump seal.
(4) Separate the torque converter from the trans-
mission.
Fig. 250 Torque Converter Lock-up Clutch
1 - TURBINE
2 - IMPELLER
3-STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
6 - PISTON
7 - COVER SHELL
8 - INTERNALLY TOOTHED DISC CARRIER
9 - CLUTCH PLATE SET
10 - EXTERNALLY TOOTHED DISC CARRIER
11 - TURBINE DAMPER
VAAUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 183
SPECIFICATIONS
TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
3500 Series 190 +10 140 +10 ±
2500 Series 240 +10 177 +10 ±
TIRES
DESCRIPTION
DESCRIPTION - TIRES
Tires are designed and engineered for each specific
vehicle. They provide the best overall performance
for normal operation. The ride and handling charac-
teristics match the vehicle's requirements. With
proper care they will give excellent reliability, trac-
tion, skid resistance, and tread life.
Driving habits have more effect on tire life than
any other factor. Careful drivers will obtain in most
cases, much greater mileage than severe use or care-
less drivers. A few of the driving habits which will
shorten the life of any tire are:
²Rapid acceleration
²Severe brake applications
²High speed driving
²Excessive speeds on turns
²Striking curbs and other obstacles
Radial-ply tires are more prone to irregular tread
wear. It is important to follow the tire rotation inter-
val shown in the section on Tire Rotation, (Refer to
22 - TIRES/WHEELS - STANDARD PROCEDURE).
This will help to achieve a greater tread life.
TIRE IDENTIFICATION
Tire type, size, aspect ratio and speed rating are
encoded in the letters and numbers imprinted on the
side wall of the tire. Refer to the chart to decipher
the tire identification code (Fig. 11).
Performance tires have a speed rating letter after
the aspect ratio number. The speed rating is not
always printed on the tire sidewall. These ratings
are:
²Qup to 100 mph
²Rup to 106 mph
²Sup to 112 mph
²Tup to 118 mph
²Uup to 124 mph²Hup to 130 mph
²Vup to 149 mph
²Zmore than 149 mph (consult the tire manu-
facturer for the specific speed rating)
An All Season type tire will have eitherM+S,M
&SorM±S(indicating mud and snow traction)
imprinted on the side wall.
TIRE CHAINS
Tire snow chains may be used oncertainmodels.
Refer to the Owner's Manual for more information.
DESCRIPTION - RADIAL ± PLY TIRES
Radial-ply tires improve handling, tread life and
ride quality, and decrease rolling resistance.
Fig. 11 Tire Identification
VATIRES/WHEELS 22 - 7