Page 1849 of 2889

OVERDRIVE CLUTCH
DESCRIPTION
The overdrive clutch (Fig. 113) is composed of the
pressure plate, clutch plates, holding discs, overdrive
piston retainer, piston, piston spacer, and snap-rings.
The overdrive clutch is the forwardmost component
in the transmission overdrive unit and is considered
a holding component. The overdrive piston retainer,piston, and piston spacer are located on the rear of
the main transmission case.
NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
OPERATION
To apply the clutch, pressure is applied between
the piston retainer and piston. The fluid pressure is
provided by the oil pump, transferred through the
control valves and passageways, and enters the
clutch through passages at the lower rear portion of
the valve body area. With pressure applied between
the piston retainer and piston, the piston moves
away from the piston retainer and compresses the
clutch pack. This action applies the clutch pack,
allowing torque to flow through the intermediate
shaft into the overdrive planetary gear set. The over-
drive clutch discs are attached to the overdrive clutch
hub while the overdrive clutch plates, reaction plate,
and pressure plate are lugged to the overdrive hous-
ing. This allows the intermediate shaft to transfer
the engine torque to the planetary gear and overrun-
ning clutch. This drives the planetary gear inside the
annulus, which is attached to the overdrive clutch
drum and output shaft, creating the desired gear
ratio. The waved snap-ring is used to cushion the
application of the clutch pack.
Fig. 113 Overdrive Clutch
1 - REACTION PLATE 2 - PRESSURE PLATE
Fig. 112 Output Shaft Rear Bearing
1 - OUTPUT SHAFT REAR BEARING
2 - OVERDRIVE HOUSING
3 - SNAP-RING
21 - 214 AUTOMATIC TRANSMISSION - 42REBR/BE
OUTPUT SHAFT REAR BEARING (Continued)
Page 1850 of 2889

OVERDRIVE OFF SWITCH
DESCRIPTION
The overdrive OFF (control) switch is located in
the shift lever arm (Fig. 114). The switch is a
momentary contact device that signals the PCM to
toggle current status of the overdrive function.
OPERATION
At key-on, overdrive operation is allowed. Pressing
the switch once causes the overdrive OFF mode to be
entered and the overdrive OFF switch lamp to be
illuminated. Pressing the switch a second time
causes normal overdrive operation to be restored and
the overdrive lamp to be turned off. The overdrive
OFF mode defaults to ON after the ignition switch is
cycled OFF and ON. The normal position for the con-
trol switch is the ON position. The switch must be in
this position to energize the solenoid and allow a 3-4
upshift. The control switch indicator light illuminates
only when the overdrive switch is turned to the OFF
position, or when illuminated by the transmission
control module.
DIAGNOSIS AND TESTING - OVERDRIVE
ELECTRICAL CONTROLS
The overdrive off switch, valve body solenoid, case
connectors and related wiring can all be tested with
a 12 volt test lamp or a volt/ohmmeter. Check conti-
nuity of each component when diagnosis indicates
this is necessary.
Switch and solenoid continuity should be checked
whenever the transmission fails to shift into fourth
gear range.
REMOVAL
(1) Using a plastic trim tool, remove the overdrive
off switch retainer from the shift lever (Fig. 115).(2) Pull the switch outwards to release it from the
connector in the lever (Fig. 116)
INSTALLATION
NOTE: There is enough slack in the wire to pull out
the connector from the lever.
(1) Pull the connector out of the lever just enough
to grasp it.
CAUTION: Be careful not to bend the pins on the
overdrive off switch. Use care when installing the
switch, as it is not indexed, and can be accidentally
installed incorrectly.
Fig. 114 Overdrive Off Switch
Fig. 115 Overdrive Off Switch Retainer
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH RETAINER
3 - PLASTIC TRIM TOOL
Fig. 116 Remove the Overdrive Off Switch
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 215
Page 1851 of 2889

(2) Install the overdrive off switch into the connec-
tor (Fig. 117)
(3) Push the overdrive off switch and wiring into
the shift lever.
(4) Install the overdrive off switch retainer onto
the shift lever.
OVERDRIVE UNIT
REMOVAL
(1) Shift transmission into PARK.
(2) Raise vehicle.
(3) Remove transfer case, if equipped.
(4) Mark propeller shaft universal joint(s) and axle
pinion yoke, or the companion flange and flange
yoke, for alignment reference at installation, if necc-
esary.
(5) Disconnect and remove the rear propeller shaft,
if necessary. (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE/PROPELLER SHAFT/PROPELLER SHAFT -
REMOVAL)
(6) Remove transmission oil pan, remove gasket,
drain oil and reinstall pan.
(7) If overdrive unit had malfunctioned, or if fluid
is contaminated, remove entire transmission. If diag-
nosis indicated overdrive problems only, remove just
the overdrive unit.(8) Support transmission with transmission jack.
(9) Remove bolts attaching overdrive unit to trans-
mission (Fig. 118).
CAUTION: Support the overdrive unit with a jack
before moving it rearward. This is necessary to pre-
vent damaging the intermediate shaft. Do not allow
the shaft to support the entire weight of the over-
drive unit.
(10) Carefully work overdrive unit off intermediate
shaft. Do not tilt unit during removal. Keep it as
level as possible.
(11) If overdrive unit does not require service,
immediately insert Alignment Tool 6227-2 in splines
of planetary gear and overrunning clutch to prevent
splines from rotating out of alignment. If misalign-
ment occurs, overdrive unit will have to be disassem-
bled in order to realign splines.
(12) Remove and retain overdrive piston thrust
bearing. Bearing may remain on piston or in clutch
hub during removal.
(13) Position drain pan on workbench.
(14) Place overdrive unit over drain pan. Tilt unit
to drain residual fluid from case.
(15) Examine fluid for clutch material or metal
fragments. If fluid contains these items, overhaul will
be necessary.
(16) If overdrive unit does not require any service,
leave alignment tool in position. Tool will prevent
accidental misalignment of planetary gear and over-
running clutch splines.
Fig. 117 Install the Overdrive Off Switch
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH WIRING CONNECTOR
3 - OVERDRIVE OFF SWITCH
Fig. 118 Overdrive Unit Bolts
1 - OVERDRIVE UNIT
2 - ATTACHING BOLTS (7)
21 - 216 AUTOMATIC TRANSMISSION - 42REBR/BE
OVERDRIVE OFF SWITCH (Continued)
Page 1852 of 2889
DISASSEMBLY
(1) Remove transmission speed sensor and O-ring
seal from overdrive case (Fig. 119).
(2) Remove overdrive piston thrust bearing (Fig.
120).
OVERDRIVE PISTON
(1) Remove overdrive piston thrust plate (Fig.
121). Retain thrust plate. It is a select fit part and
may possibly be reused.
(2) Remove intermediate shaft spacer (Fig. 122).
Retain spacer. It is a select fit part and may possibly
be reused.
Fig. 119 Transmission Speed Sensor Removal
1 - SOCKET AND WRENCH
2 - SPEED SENSOR
3 - O-RING
Fig. 120 Overdrive Piston Thrust Bearing Removal
1 - THRUST BEARING
2 - OVERDRIVE PISTON
3 - THRUST PLATE
Fig. 121 Overdrive Piston Thrust Plate Removal
1 - OVERDRIVE PISTON
2 - OVERDRIVE PISTON SPACER (SELECT FIT)
Fig. 122 Intermediate Shaft Spacer Location
1 - INTERMEDIATE SHAFT
2 - INTERMEDIATE SHAFT SPACER (SELECT FIT)
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 217
OVERDRIVE UNIT (Continued)
Page 1853 of 2889
(3) Remove overdrive piston from retainer (Fig.
123).
OVERDRIVE CLUTCH PACK
(1) Remove overdrive clutch pack wire retaining
ring (Fig. 124).
(2) Remove overdrive clutch pack (Fig. 125).
NOTE: The 42RE transmission has three clutch
discs and two clutch plates.
(3) Note position of clutch pack components for
assembly reference (Fig. 126).
Fig. 123 Overdrive Piston Removal
1 - PISTON RETAINER
2 - OVERDRIVE PISTON
Fig. 124 Removing Overdrive Clutch Pack Retaining
Ring
1 - OVERDRIVE CLUTCH PACK RETAINING RING
Fig. 125 Overdrive Clutch Pack Removal
1 - OVERDRIVE CLUTCH PACK
Fig. 126 42RE Overdrive Clutch Component
Position
1 - PRESSURE PLATE (TO FRONT)
2 - OVERDRIVE CLUTCH PACK
3 - CLUTCH DISC (3)
4 - CLUTCH PLATE (2)
5 - REACTION PLATE (TO REAR)
21 - 218 AUTOMATIC TRANSMISSION - 42REBR/BE
OVERDRIVE UNIT (Continued)
Page 1854 of 2889
OVERDRIVE GEARTRAIN
(1) Remove overdrive clutch wave spring (Fig.
127).
(2) Remove overdrive clutch reaction snap-ring
(Fig. 128). Note that snap-ring is located in same
groove as wave spring.
(3) Remove TorxŸ head screws that attach access
cover and gasket to overdrive case (Fig. 129).
(4) Remove access cover and gasket (Fig. 130).
(5) Expand output shaft bearing snap-ring with
expanding-type snap-ring pliers. Then push output
shaft forward to release shaft bearing from locating
ring (Fig. 131).
Fig. 127 Overdrive Clutch Wave
1 - WAVE SPRING
Fig. 128 Overdrive Clutch Reaction Snap-Ring
Removal
1 - REACTION RING
2 - CLUTCH HUB
Fig. 129 Access Cover Screw Removal
1 - TORX SCREWDRIVER (T25)
2 - ACCESS COVER SCREWS
Fig. 130 Access Cover And Gasket Removal
1 - ACCESS COVER AND GASKET
Fig. 131 Releasing Bearing From Locating Ring
1 - EXPAND BEARING LOCATING RING WITH SNAP-RING
PLIERS
2 - ACCESS HOLE
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 219
OVERDRIVE UNIT (Continued)
Page 1855 of 2889

(6) Lift gear case up and off geartrain assembly
(Fig. 132).
(7) Remove snap-ring that retains rear bearing on
output shaft.
(8) Remove rear bearing from output shaft (Fig.
133).
DIRECT CLUTCH, HUB AND SPRING
WARNING: THE NEXT STEP IN DISASSEMBLY
INVOLVES COMPRESSING THE DIRECT CLUTCH
SPRING. IT IS EXTREMELY IMPORTANT THAT
PROPER EQUIPMENT BE USED TO COMPRESS
THE SPRING AS SPRING FORCE IS APPROXI-
MATELY 830 POUNDS. USE SPRING COMPRESSORTOOL 6227-1 AND A HYDRAULIC SHOP PRESS
WITH A MINIMUM RAM TRAVEL OF 5-6 INCHES.
THE PRESS MUST ALSO HAVE A BED THAT CAN
BE ADJUSTED UP OR DOWN AS REQUIRED.
RELEASE CLUTCH SPRING TENSION SLOWLY AND
COMPLETELY TO AVOID PERSONAL INJURY.
(1) Mount geartrain assembly in shop press (Fig.
134).
(2) Position Compressor Tool 6227-1 on clutch hub
(Fig. 134). Support output shaft flange with steel
press plates as shown and center assembly under
press ram.
(3) Apply press pressure slowly. Compress hub and
spring far enough to expose clutch hub retaining ring
and relieve spring pressure on clutch pack snap-ring
(Fig. 134).
Fig. 134 Geartrain Mounted In Shop Press
1 - PRESS RAM
2 - SPECIAL TOOL C-3995-A (OR SIMILAR TOOL)
3 - CLUTCH HUB
4 - PLATES
5 - PRESS BED
6 - SPECIAL TOOL 6227-1
Fig. 132 Removing Gear Case From Geartrain
Assembly
1 - GEARTRAIN ASSEMBLY
2 - GEAR CASE
Fig. 133 Rear Bearing Removal
1 - OUTPUT SHAFT
2 - REAR BEARING
3 - SNAP-RING
21 - 220 AUTOMATIC TRANSMISSION - 42REBR/BE
OVERDRIVE UNIT (Continued)
Page 1856 of 2889
(4) Remove direct clutch pack snap-ring (Fig. 135).
(5) Remove direct clutch hub retaining ring (Fig.
136).
(6) Release press load slowly and completely (Fig.
137).
(7) Remove Special Tool 6227-1. Then remove
clutch pack from hub (Fig. 137).
Fig. 135 Direct Clutch Pack Snap-Ring Removal
1 - CLUTCH HUB
2 - SPECIAL TOOL 6227-1
3 - DIRECT CLUTCH PACK SNAP-RING
4 - PRESS PLATES
5 - CLUTCH DRUM
Fig. 136 Direct Clutch Hub Retaining Ring Removal
1 - SPECIAL TOOL 6227-1
2 - CLUTCH HUB RETAINING RING
3 - PRESS BED
4 - PRESS PLATES
Fig. 137 Direct Clutch Pack Removal
1 - SPECIAL TOOL 6227-1
2 - DIRECT CLUTCH HUB
3 - DIRECT CLUTCH PACK
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 221
OVERDRIVE UNIT (Continued)