(4) Transmission speed sensor can be installed at
this time if desired. However, it is recommended that
sensor not be installed until after overdrive unit is
secured to transmission.
OVERDRIVE PISTON
(1) Install new seals on overdrive piston.
(2) Stand transmission case upright on bellhous-
ing.
(3) Position Guide Ring 8114-1 on outer edge of
overdrive piston retainer.
(4) Position Seal Guide 8114-3 on inner edge of
overdrive piston retainer.
(5) Install overdrive piston in overdrive piston
retainer by:
(a) Aligning locating lugs on overdrive piston to
the two mating holes in retainer.(b) Lubricate overdrive piston seals with Mopart
Door Ease, or equivalent.
(c) Install piston over Seal Guide 8114-3 and
inside Guide Ring 8114-1.
(d) Push overdrive piston into position in
retainer.
(e) Verify that the locating lugs entered the lug
bores in the retainer.
(6) Install intermediate shaft spacer on intermedi-
ate shaft.
(7) Install overdrive piston thrust plate on over-
drive piston.
(8) Install overdrive piston thrust bearing on over-
drive piston.
(9) Install transmission speed sensor and o-ring
seal in overdrive case.
INSTALLATION
(1) Be sure overdrive unit Alignment Tool 6227-2
is fully seated before moving unit. If tool is not
seated and gear splines rotate out of alignment, over-
drive unit will have to be disassembled in order to
realign splines.
(2) If overdrive piston retainer was not removed
during service and original case gasket is no longer
reusable, prepare new gasket by trimming it.
(3) Cut out old case gasket around piston retainer
with razor knife (Fig. 176).
(4) Use old gasket as template and trim new gas-
ket to fit.
(5) Position new gasket over piston retainer and
on transmission case. Use petroleum jelly to hold
gasket in place if necessary. Do not use any type of
sealer to secure gasket. Use petroleum jelly only.
Fig. 174 Overdrive Piston Thrust Plate Measurement
1 - SPECIAL TOOL 6311
2 - DIRECT CLUTCH HUB THRUST BEARING SEAT
3 - SPECIAL TOOL C-4962
Fig. 175 Overdrive Piston Thrust Plate Selection
Fig. 176 Trimming Overdrive Case Gasket
1 - GASKET
2 - SHARP KNIFE
21 - 750 AUTOMATIC TRANSMISSION - 47REBR/BE
OVERDRIVE UNIT (Continued)
(6) Install selective spacer on intermediate shaft, if
removed. Spacer goes in groove just rearward of
shaft rear splines (Fig. 177).
(7) Install thrust bearing in overdrive unit sliding
hub. Use petroleum jelly to hold bearing in position.
CAUTION: Be sure the shoulder on the inside diam-
eter of the bearing is facing forward.
(8) Verify that splines in overdrive planetary gear
and overrunning clutch hub are aligned with Align-
ment Tool 6227-2. Overdrive unit cannot be installed
if splines are not aligned. If splines have rotated out
of alignment, unit will have to be disassembled to
realign splines.
(9) Carefully slide Alignment Tool 6227-2 out of
overdrive planetary gear and overrunning clutch
splines.
(10) Raise overdrive unit and carefully slide it
straight onto intermediate shaft. Insert park rod into
park lock reaction plug at same time. Avoid tilting
overdrive during installation as this could cause
planetary gear and overrunning clutch splines to
rotate out of alignment. If this occurs, it will be nec-
essary to remove and disassemble overdrive unit to
realign splines.
(11) Work overdrive unit forward on intermediate
shaft until seated against transmission case.
(12) Install bolts attaching overdrive unit to trans-
mission unit. Tighten bolts in diagonal pattern to 34
N´m (25 ft-lbs).
(13) Connect the transmission speed sensor and
overdrive wiring connectors.
(14) Install the transfer case, if equipped.
(15) Align and install rear propeller shaft, if nec-
essary. (Refer to 3 - DIFFERENTIAL & DRIVELINE/
PROPELLER SHAFT/PROPELLER SHAFT -
INSTALLATION)OVERRUNNING CLUTCH
CAM/OVERDRIVE PISTON
RETAINER
DESCRIPTION
The overrunning clutch (Fig. 178) consists of an
inner race, an outer race (or cam), rollers and
springs, and the spring retainer. The number of roll-
ers and springs depends on what transmission and
which overrunning clutch is being dealt with.
OPERATION
As the inner race is rotated in a clockwise direction
(as viewed from the front of the transmission), the
race causes the rollers to roll toward the springs,
causing them to compress against their retainer. The
compression of the springs increases the clearance
between the rollers and cam. This increased clear-
ance between the rollers and cam results in a free-
wheeling condition. When the inner race attempts to
rotate counterclockwise, the action causes the rollers
to roll in the same direction as the race, aided by the
pushing of the springs. As the rollers try to move in
the same direction as the inner race, they are
wedged between the inner and outer races due to the
design of the cam. In this condition, the clutch is
locked and acts as one unit.
DISASSEMBLY
(1) Remove the overdrive piston (Fig. 179).
(2) Remove the overdrive piston retainer bolts.
(3) Remove overdrive piston retainer.
Fig. 177 Intermediate Shaft Selective Spacer
Location
1 - SELECTIVE SPACER
2 - SPACER GROOVE
3 - INTERMEDIATE SHAFT
Fig. 178 Overrunning Clutch
1 - OUTER RACE (CAM)
2 - ROLLER
3 - SPRING
4 - SPRING RETAINER
5 - INNER RACE (HUB)
BR/BEAUTOMATIC TRANSMISSION - 47RE 21 - 751
OVERDRIVE UNIT (Continued)
plunger also contribute to the response speed possi-
ble by a particular solenoid design.
A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
SPEED SENSOR
DESCRIPTION
The speed sensor (Fig. 223) is located in the over-
drive gear case. The sensor is positioned over the
park gear and monitors transmission output shaft
rotating speed.
OPERATION
Speed sensor signals are triggered by the park
gear lugs as they rotate past the sensor pickup face.
Input signals from the sensor are sent to the trans-
mission control module for processing. Signals from
this sensor are shared with the powertrain control
module.
THROTTLE VALVE CABLE
DESCRIPTION
Transmission throttle valve cable (Fig. 224) adjust-
ment is extremely important to proper operation.
This adjustment positions the throttle valve, which
controls shift speed, quality, and part-throttle down-
shift sensitivity.
If cable setting is too loose, early shifts and slip-
page between shifts may occur. If the setting is too
tight, shifts may be delayed and part throttle down-
shifts may be very sensitive.
Fig. 223 Transmission Output Speed Sensor
1 - TRANSMISSION OUTPUT SHAFT SPEED SENSOR
2 - SEAL
Fig. 224 Throttle Valve Cable Attachment - At
Engine
1 - THROTTLE VALVE CABLE
2 - CABLE BRACKET
3 - THROTTLE BODY LEVER
4 - ACCELERATOR CABLE
5 - SPEED CONTROL CABLE
21 - 770 AUTOMATIC TRANSMISSION - 47REBR/BE
SOLENOID (Continued)
vehicle is parked for lengthy periods. The valve check
ball is spring loaded and has an opening pressure of
approximately 2 psi.
The valve is serviced as an assembly; it is not
repairable. Do not clean the valve if restricted, or
contaminated by sludge, or debris. If the valve fails,
or if a transmission malfunction occurs that gener-
ates significant amounts of sludge and/or clutch par-
ticles and metal shavings, the valve must be
replaced.
The valve must be removed whenever the cooler
and lines are reverse flushed. The valve can be flow
tested when necessary. The procedure is exactly the
same as for flow testing a cooler.
If the valve is restricted, installed backwards, or in
the wrong line, it will cause an overheating condition
and possible transmission failure.
CAUTION: The drainback valve is a one-way flow
device. It must be properly oriented in terms of flow
direction for the cooler to function properly. The
valve must be installed in the pressure line. Other-
wise flow will be blocked and would cause an over-
heating condition and eventual transmission failure.
TRANSMISSION
TEMPERATURE SENSOR
DESCRIPTION
Transmission fluid temperature readings are sup-
plied to the transmission control module by the ther-
mistor (Fig. 238). The temperature readings are used
to control engagement of the fourth gear overdrive
clutch, the converter clutch, and governor pressure.
Normal resistance value for the thermistor at room
temperature is approximately 1000 ohms.
The thermistor is part of the governor pressure
sensor assembly and is immersed in transmission
fluid at all times.
OPERATION
The PCM prevents engagement of the converter
clutch and overdrive clutch, when fluid temperature
is below approximately 10ÉC (50ÉF).
If fluid temperature exceeds 126ÉC (260ÉF), the
PCM causes a 4-3 downshift and engage the con-
verter clutch. Engagement is according to the third
gear converter clutch engagement schedule.
The overdrive OFF lamp in the instrument panel
illuminates when the shift back to third occurs. The
transmission will not allow fourth gear operation
until fluid temperature decreases to approximately
110ÉC (230ÉF).
Fig. 237 Typical Method Of Checking Converter
Seating
1 - SCALE
2 - STRAIGHTEDGE
Fig. 238 Governor Pressure Sensor
1 - GOVERNOR BODY
2 - GOVERNOR PRESSURE SENSOR/TRANSMISSION FLUID
TEMPERATURE THERMISTOR
BR/BEAUTOMATIC TRANSMISSION - 47RE 21 - 779
TORQUE CONVERTER DRAINBACK VALVE (Continued)
REMOVAL
The valve body can be removed for service without
having to remove the transmission assembly.
The valve body can be disassembled for cleaning
and inspection of the individual components.
The only replaceable valve body components are:
²Manual lever.
²Manual lever washer, seal, E-clip, and shaft
seal.
²Manual lever detent ball.
²Throttle lever.
²Fluid filter.
²Pressure adjusting screw bracket.
²Governor pressure solenoid.
²Governor pressure sensor (includes transmission
temperature thermistor).
²Converter clutch/overdrive solenoid assembly
and harness .
²Governor housing gasket.
²Solenoid case connector O-rings.
(1) Shift transmission into NEUTRAL.
(2) Raise vehicle.
(3) Remove gearshift and throttle levers from shaft
of valve body manual lever.
(4) Disconnect wires at solenoid case connector
(Fig. 263).
(5) Position drain pan under transmission oil pan.
(6) Remove transmission oil pan and gasket.
(7) Remove fluid filter from valve body.(8) Remove bolts attaching valve body to transmis-
sion case.
(9) Lower valve body enough to remove accumula-
tor piston and springs.
(10) Work manual lever shaft and electrical con-
nector out of transmission case.
(11) Lower valve body, rotate valve body away
from case, pull park rod out of sprag, and remove
valve body (Fig. 264).
Fig. 262 Boost Valve After Lock-upFig. 263 Transmission Case Connector
1 - SOLENOID CASE CONNECTOR
2 - PARK/NEUTRAL POSITION SWITCH
Fig. 264 Valve Body
1 - VALVE BODY
2 - WIRE HARNESS
3 - PARK ROD
4 - GOVERNOR PRESSURE SOLENOID
5 - GOVERNOR PRESSURE SENSOR
21 - 798 AUTOMATIC TRANSMISSION - 47REBR/BE
VALVE BODY (Continued)
DISASSEMBLY
CAUTION: Do not clamp any valve body component
in a vise. This practice can damage the component
resulting in unsatisfactory operation after assembly
and installation. Do not use pliers to remove any of
the valves, plugs or springs and do not force any of
the components out or into place. The valves and
valve body housings will be damaged if force is
used. Tag or mark the valve body springs for refer-
ence as they are removed. Do not allow them to
become intermixed.
(1) Disconnect wires from governor pressure sen-
sor and solenoid.
(2) Remove screws attaching governor body and
retainer plate to transfer plate.
(3) Remove retainer plate, governor body and gas-
ket from transfer plate.
(4) Remove governor pressure sensor from gover-
nor body.
(5) Remove governor pressure solenoid by pulling
it straight out of bore in governor body. Remove and
discard solenoid O-rings if worn, cut, or torn.
(6) Remove small shoulder bolt that secures sole-
noid harness case connector to 3-4 accumulator hous-
ing (Fig. 265). Retain shoulder bolt. Either tape it to
harness or thread it back into accumulator housing
after connector removal.
(7) Unhook overdrive/converter solenoid harness
from 3-4 accumulator cover plate (Fig. 266).
(8) Turn valve body over and remove screws that
attach overdrive/converter solenoid assembly to valve
body (Fig. 267).
(9) Remove solenoid and harness assembly from
valve body (Fig. 268).
(10) Remove boost valve cover (Fig. 269).
(11) Remove boost valve retainer, valve spring and
boost valve (Fig. 270).
Fig. 265 Solenoid Harness Case Connector
Shoulder Bolt
1 - SOLENOID HARNESS CASE CONNECTOR
2 - 3-4 ACCUMULATOR HOUSING
Fig. 266 Solenoid Harness Routing
1 - OVERDRIVE/CONVERTER SOLENOID WIRE HARNESS
2 - 3-4 ACCUMULATOR COVER PLATE
BR/BEAUTOMATIC TRANSMISSION - 47RE 21 - 799
VALVE BODY (Continued)
(12) Secure detent ball and spring with Retainer
Tool 6583 (Fig. 271).
(13) Remove park rod E-clip and separate rod from
manual lever (Fig. 272).
(14) Remove E-clip and washer that retains throt-
tle lever shaft in manual lever (Fig. 273).
(15) Remove manual lever and throttle lever (Fig.
274). Rotate and lift manual lever off valve body and
throttle lever shaft. Then slide throttle lever out of
valve body.
(16) Position pencil magnet next to detent housing
to catch detent ball and spring. Then carefully
remove Retainer Tool 6583 and remove detent ball
and spring (Fig. 275).
Fig. 267 Solenoid Assembly Screws
1 - OVERDRIVE/CONVERTER CLUTCH SOLENOID ASSEMBLY
2 - HARNESS
Fig. 268 Solenoid Assembly
1 - GOVERNOR SOLENOID WIRES
2 - CONVERTER CLUTCH SOLENOID
3 - SOLENOID SCREWS
4 - GOVERNOR SENSOR WIRES
5 - OVERDRIVE SOLENOID
6 - HARNESS
7 - CASE CONNECTOR
Fig. 269 Boost Valve Cover Location
1 - BOOST VALVE HOUSING AND COVER
2 - BOOST VALVE TUBE
Fig. 270 Boost Valve Components
1 - SPRING AND VALVE RETAINER
2 - COVER SCREWS
3 - BOOST VALVE COVER
4 - BOOST VALVE PLUG
5 - BOOST VALVE
6 - BOOST VALVE SPRING
21 - 800 AUTOMATIC TRANSMISSION - 47REBR/BE
VALVE BODY (Continued)
VALVE BODY LOWER HOUSING
(1) Remove timing valve cover.
(2) Remove 3-4 timing valve and spring.
(3) Remove 3-4 quick fill valve, spring and plug.
(4) Remove 3-4 shift valve and spring.
(5) Remove converter clutch valve, spring and plug
(Fig. 293).
(6) Remove converter clutch timing valve, retainer
and valve spring.
3-4 ACCUMULATOR HOUSING
(1) Remove end plate from housing.
(2) Remove piston spring.
(3) Remove piston. Remove and discard piston
seals (Fig. 294).
CLEANING
Clean the valve housings, valves, plugs, springs,
and separator plates with a standard parts cleaningsolution only. Do not use gasoline, kerosene, or any
type of caustic solution.
Do not immerse any of the electrical components in
cleaning solution. Clean the governor solenoid and
sensor and the dual solenoid and harness assembly
by wiping them off with dry shop towels only.
Dry all except the electrical parts with compressed
air. Make sure all passages are clean and free from
obstructions.Do not use rags or shop towels to
dry or wipe off valve body components. Lint
from these materials can stick to valve body
parts, interfere with valve operation, and clog
filters and fluid passages.
Wipe the governor pressure sensor and solenoid
valve with dry, lint free shop towels only. The O-rings
on the sensor and solenoid valve are the only service-
able components. Be sure the vent ports in the sole-
noid valve are open and not blocked by dirt or debris.
Replace the valve and/or sensor only when DRB scan
tool diagnosis indicates this is necessary. Or, if either
Fig. 292 Upper Housing Shift Valve and Pressure Plug Locations
1 - UPPER HOUSING 8 - RETAINER
2 - 1-2 SHIFT VALVE AND SPRING 9 - 1-2 SHIFT CONTROL VALVE AND SPRING
3 - 2-3 SHIFT VALVE AND SPRING 10 - PRESSURE PLUG COVER
4 - 2-3 THROTTLE PLUG 11 - LINE PRESSURE PLUG
5 - LIMIT VALVE HOUSING 12 - PLUG SLEEVE
6 - LIMIT VALVE COVER 13 - THROTTLE PRESSURE SPRING AND PLUG
7 - LIMIT VALVE AND SPRING
21 - 808 AUTOMATIC TRANSMISSION - 47REBR/BE
VALVE BODY (Continued)