Page 1673 of 2199

BOOST VALVE
The boost valve (Fig. 277) provides increased fluid
apply pressure to the overdrive clutch during 3-4
upshifts (Fig. 278), and when accelerating in fourth
gear. The boost valve also serves to increase line
pressure during torque converter lock-up.
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. 279).
(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. 280).
Fig. 277 Boost Valve Before Lock-up
Fig. 278 Boost Valve After Lock-up
Fig. 279 Transmission Case Connector
1 - SOLENOID CASE CONNECTOR
2 - PARK/NEUTRAL POSITION SWITCH
21 - 154 AUTOMATIC TRANSMISSION - 42REWJ
VALVE BODY (Continued)
Page 1674 of 2199

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. 281). Retain shoulder bolt. Either tape it toharness or thread it back into accumulator housing
after connector removal.
(7) Unhook overdrive/converter solenoid harness
from 3-4 accumulator cover plate (Fig. 282).
(8) Turn valve body over and remove screws that
attach overdrive/converter solenoid assembly to valve
body (Fig. 283).
(9) Remove solenoid and harness assembly from
valve body (Fig. 284).
(10) Remove boost valve cover (Fig. 285).
(11) Remove boost valve retainer, valve spring and
boost valve (Fig. 286).
Fig. 280 Valve Body
1 - VALVE BODY
2 - WIRE HARNESS
3 - PARK ROD
4 - GOVERNOR PRESSURE SOLENOID
5 - GOVERNOR PRESSURE SENSOR
Fig. 281 Solenoid Harness Case Connector
Shoulder Bolt
1 - SOLENOID HARNESS CASE CONNECTOR
2 - 3-4 ACCUMULATOR HOUSING
Fig. 282 Unhooking Solenoid Harness From
Accumulator Cover Plate
1 - OVERDRIVE/CONVERTER SOLENOID WIRE HARNESS
2 - 3-4 ACCUMULATOR COVER PLATE
WJAUTOMATIC TRANSMISSION - 42RE 21 - 155
VALVE BODY (Continued)
Page 1675 of 2199

(12) Secure detent ball and spring with Retainer
Tool 6583 (Fig. 287).
(13) Remove park rod E-clip and separate rod from
manual lever (Fig. 288).
(14) Remove E-clip and washer that retains throt-
tle lever shaft in manual lever (Fig. 289).
(15) Remove manual lever and throttle lever (Fig.
290). Rotate and lift manual lever off valve body and
throttle lever shaft. Then slide throttle lever out of
valve body.
Fig. 283 Solenoid Assembly Screws
1 - OVERDRIVE/CONVERTER CLUTCH SOLENOID ASSEMBLY
2 - HARNESS
Fig. 284 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. 285 Boost Valve
1 - BOOST VALVE HOUSING AND COVER
2 - BOOST VALVE TUBE
Fig. 286 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 - 156 AUTOMATIC TRANSMISSION - 42REWJ
VALVE BODY (Continued)
Page 1676 of 2199
(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. 291).
(17) Remove screws attaching pressure adjusting
screw bracket to valve body and transfer plate (Fig.
292). Hold bracket firmly against spring tension
while removing last screw.
Fig. 287 Detent Ball And Spring
1 - SPECIAL TOOL 6583 POSITIONED ON DETENT HOUSING
Fig. 288 Park Rod
1 - MANUAL LEVER
2 - E-CLIP
3 - PARK ROD
Fig. 289 Throttle Lever E-Clip And Washer
1 - THROTTLE LEVER SHAFT
2 - E-CLIP AND WASHER
3 - MANUAL SHAFT
Fig. 290 Manual And Throttle Lever
1 - PARK ROD
2 - MANUAL LEVER ASSEMBLY
3 - THROTTLE LEVER
WJAUTOMATIC TRANSMISSION - 42RE 21 - 157
VALVE BODY (Continued)
Page 1677 of 2199

(18) Remove adjusting screw bracket, line pressure
adjusting screw, pressure regulator valve spring and
switch valve spring (Fig. 293). Do not remove throttle
pressure adjusting screw from bracket and do not
disturb setting of either adjusting screw during
removal.
(19) Turn upper housing over and remove switch
valve, regulator valve and spring, and manual valve
(Fig. 294).
(20) Remove kickdown detent, kickdown valve, and
throttle valve and spring (Fig. 294).
(21) Loosen left-side 3-4 accumulator housing
attaching screw about 2-3 threads. Then remove cen-
ter and right-side housing attaching screws (Fig.
295).
(22) Carefully rotate 3-4 accumulator housing
upward and remove 3-4 shift valve spring and con-
verter clutch valve plug and spring (Fig. 296).
(23) Remove left-side screw and remove 3-4 accu-
mulator housing from valve body (Fig. 297).
(24) Bend back tabs on boost valve tube brace (Fig.
298).
Fig. 291 Detent Ball And Spring
1 - DETENT HOUSING
2 - DETENT SPRING
3 - DETENT BALL
4 - PENCIL MAGNET
Fig. 292 Adjusting Screw Bracket Fastener
1 - T25 TORXŸ BIT
2 - REMOVE THESE SCREWS FIRST
3 - BRACKET
4 - BRACKET
5 - REMOVE THIS SCREW LAST
Fig. 293 Adjusting Screw Bracket And Spring
1 - SWITCH VALVE SPRING
2 - LINE PRESSURE SCREW
3 - THROTTLE PRESSURE ADJUSTING SCREW
4 - ADJUSTING SCREW BRACKET
5 - PRESSURE REGULATOR VALVE SPRING
21 - 158 AUTOMATIC TRANSMISSION - 42REWJ
VALVE BODY (Continued)
Page 1678 of 2199
Fig. 294 Upper Housing Control Valve Locations
1 - UPPER HOUSING 8 - MANUAL VALVE
2 - REGULATOR VALVE 9 - 1-2 GOVERNOR PLUG
3 - SWITCH VALVE 10 - GOVERNOR PLUG COVER
4 - REGULATOR VALVE SPRING 11 - THROTTLE PLUG
5 - KICKDOWN VALVE 12 - 2-3 GOVERNOR PLUG
6 - KICKDOWN DETENT 13 - SHUTTLE VALVE PRIMARY SPRING
7 - THROTTLE VALVE AND SPRING
Fig. 295 Accumulator Housing Screw Locations
1 - LOOSEN THIS SCREW
2 - REMOVE THESE SCREWS
3 - 3-4 ACCUMULATOR HOUSINGFig. 296 3-4 Shift And Converter Clutch Valve
Springs And Plug
1 - ACCUMULATOR HOUSING
2 - CONVERTER CLUTCH VALVE SPRING
3 - CLUTCH VALVE PLUG
4 - 3-4 SHIFT VALVE SPRING
WJAUTOMATIC TRANSMISSION - 42RE 21 - 159
VALVE BODY (Continued)
Page 1679 of 2199

(25) Remove boost valve connecting tube (Fig.
299). Disengage tube from upper housing port first.
Then rock opposite end of tube back and forth to
work it out of lower housing.
CAUTION: Do not use tools to loosen or pry the
connecting tube out of the valve body housings.
Loosen and remove the tube by hand only.
(26) Turn valve body over so lower housing is fac-
ing upward (Fig. 300). In this position, the two check
balls in upper housing will remain in place and not
fall out when lower housing and separator plate are
removed.
(27) Remove screws attaching valve body lower
housing to upper housing and transfer plate (Fig.300). Note position of boost valve tube brace for
assembly reference.
(28) Remove lower housing and overdrive separa-
tor plate from transfer plate (Fig. 300).
(29) Remove the ECE check ball from the transfer
plate (Fig. 301). The ECE check ball is approximately
4.8 mm (3/16 in.) in diameter.
(30) Remove transfer plate from upper housing
(Fig. 302).
(31) Turn transfer plate over so upper housing sep-
arator plate is facing upward.
(32) Remove upper housing separator plate from
transfer plate (Fig. 303). Note position of filter in
separator plate for assembly reference.
(33) Remove rear clutch and rear servo check balls
from transfer plate. Note check ball location for
assembly reference (Fig. 304).
Fig. 297 Accumulator Housing, Valve Springs And
Plug
1 - 3-4 SHIFT VALVE SPRING
2 - CONVERTER CLUTCH VALVE SPRING AND PLUG
3 - 3-4 ACCUMULATOR HOUSING
Fig. 298 Boost Valve Tube Brace
1 - BOOST VALVE TUBE
2 - TUBE BRACE (DOUBLE TAB)
Fig. 299 Boost Valve Tube
1 - BOOST VALVE TUBE
2 - LOWER HOUSING
3 - DISENGAGE THIS END OF TUBE FIRST
4 - UPPER HOUSING
Fig. 300 Lower Housing
1 - LOWER HOUSING
2 - OVERDRIVE SEPARATOR PLATE
3 - TRANSFER PLATE AND UPPER HOUSING
21 - 160 AUTOMATIC TRANSMISSION - 42REWJ
VALVE BODY (Continued)
Page 1680 of 2199
Fig. 301 ECE Check Ball
1 - ECE CHECK BALL (3/169)
Fig. 302 Transfer Plate
1 - UPPER HOUSING
2 - TRANSFER PLATE
Fig. 303 Upper Housing Separator Plate
1 - TRANSFER PLATE
2 - UPPER HOUSING SEPARATOR PLATE
3 - FILTER SCREEN
4 - BRACE
Fig. 304 Rear Clutch And Rear Servo Check Ball
1 - REAR CLUTCH CHECK BALL
2 - REAR SERVO CHECK BALL
3 - TRANSFER PLATE
WJAUTOMATIC TRANSMISSION - 42RE 21 - 161
VALVE BODY (Continued)