
ADJUSTMENTS - BRAKE TRANSMISSION
SHIFT INTERLOCK
Correct cable adjustment is important to proper
interlock operation. The gearshift cable must be cor-
rectly adjusted in order to shift out of PARK.
ADJUSTMENT PROCEDURE
(1) Remove the steering column trim as necessary
for access to the brake transmission shift interlock.
(2) Shift the transmission into the PARK position.
(3) Pull upward on both the BTSI lock tab and the
gearshift cable lock tab (Fig. 77).
(4) Verify that the shift lever is in the PARK posi-
tion.
(5) Verify positive engagement of the transmission
park lock by attempting to rotate the propeller shaft.
The shaft will not rotate when the park lock is
engaged.
(6) Turn ignition switch to LOCK position.Be
sure ignition key cylinder is in the LOCK posi-
tion. Cable will not adjust correctly in any
other position.
(7) Ensure that the cable is free to self-adjust by
pushing cable rearward and releasing.
(8) Push the gearshift cable lock tab down until it
snaps in place.
(9) Locate the BTSI alignment hole in the bottom
of the BTSI mechanism between the BTSI lock tab
and the BTSI connector.
(10) Move the BTSI assembly up or down on the
gearshift cable until an appropriate size drill bit can
be inserted into the alignment hole and through the
assembly.(11) Push the BTSI lock tab down until it snaps
into place and remove the drill bit.
(12) Install any steering column trim previously
removed.
BTSI FUNCTION CHECK
(1) Verify removal of ignition key allowed in PARK
position only.
(2) When the shift lever is in PARK, the ignition
key cylinder should rotate freely from off to lock.
When the shifter is in any other position, the ignition
key should not rotate from off to lock.
(3) Shifting out of PARK should be possible when
the ignition key cylinder is in the off position.
(4)
Shifting out of PARK should not be possible while
applying normal force, and ignition key cylinder is in
the run or start positions, unless the foot brake pedal is
depressed approximately 1/2 inch (12mm).
(5) Shifting out of PARK should not be possible
when the ignition key cylinder is in the accessory or
lock position.
(6) Shifting between any gear and NEUTRAL, or
PARK, may be done without depressing foot brake
with ignition switch in run or start positions.
(7) Engine starts must be possible with shifter
lever in PARK or NEUTRAL positions only. Engine
starts must not be possible in any position other than
PARK or NEUTRAL.
(8) With shifter lever in the:
²PARK position - Apply upward force on the shift
arm and remove pressure. Engine starts must be
possible.
²PARK position - Apply downward force on the
shift arm and remove pressure. Engine starts must
be possible.
²NEUTRAL position - Normal position. Engine
starts must be possible.
²NEUTRAL position - Engine running and brakes
applied, apply upward force on the shift arm. Trans-
mission shall not be able to shift from neutral to
reverse.
ELECTRONIC GOVERNOR
DESCRIPTION
Governor pressure is controlled electronically. Com-
ponents used for governor pressure control include:
²Governor body
²Valve body transfer plate
²Governor pressure solenoid valve
²Governor pressure sensor
²Fluid temperature thermistor
²Throttle position sensor (TPS)
²Transmission speed sensor
²Powertrain control module (PCM)
Fig. 77 Brake Transmission Interlock Mechanism
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
21 - 376 AUTOMATIC TRANSMISSION - 48REDR
BRAKE TRANSMISSION SHIFT INTERLOCK SYSTEM (Continued)

(4) Lower the vehicle.
(5) Remove the dash panel insulation pad as nec-
essary to access the gearshift cable grommet (Fig.
106).
(6) Remove grommet from the dash panel.
(7) Remove any steering column trim necessary to
access the gearshift cable and BTSI mechanism.
(8) Disconnect the BTSI wiring connector.
(9) Disconnect cable at lower column bracket and
shift lever pin and pull the cable through the dash
panel opening into the vehicle (Fig. 107).
(10) Remove gearshift cable from vehicle.INSTALLATION
(1) Route the transmission end of the gearshift
cable through the opening in the dash panel (Fig.
108).
(2) Seat the cable grommet into the dash panel
opening.
(3) Snap the cable into the steering column
bracket so the retaining ears (Fig. 109) are engaged
and snap the cable eyelet onto the shift lever ball
stud.
Fig. 106 Gearshift Cable at the Dash Panel
1 - GEARSHIFT CABLE
2 - GROMMET
Fig. 107 Gearshift Cable at Steering Column
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
Fig. 108 Gearshift Cable at the Dash Panel
1 - GEARSHIFT CABLE
2 - GROMMET
Fig. 109 Gearshift Cable at Steering Column
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
21 - 390 AUTOMATIC TRANSMISSION - 48REDR
GEARSHIFT CABLE (Continued)

(4) Raise the vehicle.
(5) Place the transmission manual shift lever in
the ªPARKº detent (rearmost) position and rotate
prop shaft to ensure transmission is in PARK.
(6) Route the gearshift cable through the transmis-
sion mounting bracket and secure the cable by snap-
ping the cable retaining ears into the transmission
bracket and snapping the cable eyelet on the manual
shift lever ball stud.
(7) Lower vehicle.
(8) Lock the shift cable adjustment by pressing the
cable adjuster lock tab downward until it snaps into
place.
(9) Check for proper operation of the transmission
range sensor.
(10) Adjust the gearshift cable and BTSI mecha-
nism as necessary.
ADJUSTMENTS
GEARSHIFT CABLE
Check adjustment by starting the engine in PARK
and NEUTRAL. Adjustment is CORRECT if the
engine starts only in these positions. Adjustment is
INCORRECT if the engine starts in one but not both
positions. If the engine starts in any position other
than PARK or NEUTRAL, or if the engine will not
start at all, the transmission range sensor may be
faulty.
Gearshift Adjustment Procedure
(1) Shift transmission into PARK.
(2) Release cable adjuster lock tab (underneath the
steering column) (Fig. 110) to unlock cable.
(3) Raise vehicle.
(4) Disengage the cable eyelet from the transmis-
sion manual shift lever.(5) Verify transmission shift lever is in PARK
detent by moving lever fully rearward. Last rearward
detent is PARK position.
(6) Verify positive engagement of transmission
park lock by attempting to rotate propeller shaft.
Shaft will not rotate when park lock is engaged.
(7) Snap the cable eyelet onto the transmission
manual shift lever.
(8) Lower vehicle.
(9) Lock shift cable by pressing cable adjuster lock
tab downward until it snaps into place.
(10) Check engine starting. Engine should start
only in PARK and NEUTRAL
Fig. 110 Gearshift Cable at Steering Column
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 391
GEARSHIFT CABLE (Continued)

DISASSEMBLY
(1) Mark position of support in oil pump body for
assembly alignment reference. Use scriber or paint to
make alignment marks.
(2) Place pump body on two wood blocks.
(3) Remove reaction shaft support bolts and sepa-
rate support from pump body (Fig. 112).
(4) Remove pump inner and outer gears (Fig. 113).
(5) Remove o-ring seal from pump body (Fig. 114).
Discard seal after removal.
(6) Remove oil pump seal with Remover Tool
C-3981. Discard seal after removal.
CLEANING
Clean pump and support components with solvent
and dry them with compressed air.
INSPECTION
Check condition of the seal rings and thrust
washer on the reaction shaft support. The seal rings
do not need to be replaced unless cracked, broken, or
severely worn.
Inspect the pump and support components. Replace
the pump or support if the seal ring grooves or
machined surfaces are worn, scored, pitted, or dam-
aged. Replace the pump gears if pitted, worn
chipped, or damaged.
Inspect the pump bushing. Then check the reaction
shaft support bushing. Replace either bushing only if
heavily worn, scored or damaged. It is not necessary
to replace the bushings unless they are actually dam-
aged.
Clearance between outer gear and reaction shaft
housing should be 0.010 to 0.063 mm (0.0004 to
0.0025 in.). Clearance between inner gear and reac-
tion shaft housing should be 0.010 to 0.063 mm
(0.0004 to 0.0025 in.). Both clearances can be mea-sured at the same time by installing the gears in the
pump body and measure pump component clearances
as follows:
(1) Position an appropriate piece of PlastigageŸ
across both gears.
(2) Align the plastigage to a flat area on the reac-
tion shaft housing.
(3) Install the reaction shaft to the pump housing.
(4) Separate the reaction shaft housing from the
pump housing and measure the PlastigageŸ follow-
ing the instructions supplied with it.
Clearance between inner gear tooth and outer gear
should be 0.051 to 0.19 mm (0.002 to 0.0075 in.).
Measure clearance with an appropriate feeler gauge
(Fig. 115).
Clearance between outer gear and pump housing
should be 0.10 to 0.229 mm (0.004 to 0.009 in.). Mea-
sure clearance with an appropriate feeler gauge.
ASSEMBLY
(1) Lubricate pump gears with transmission fluid
and install them in pump body.
(2) Install thrust washer on reaction shaft support
hub. Lubricate washer with petroleum jelly or trans-
mission fluid before installation.
(3) If reaction shaft seal rings are being replaced,
install new seal rings on support hub. Lubricate seal
rings with transmission fluid or petroleum jelly after
installation. Squeeze each ring until ring ends are
securely hooked together.
Fig. 112 Reaction Shaft Support
1 - OIL PUMP
2 - REACTION SHAFT SUPPORT
Fig. 113 Pump Gears
1 - GEAR BORE
2 - PUMP BODY
3 - INNER GEAR
4 - OUTER GEAR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 393
OIL PUMP (Continued)

(2) Remove sun gear and spring plate. Then
remove planetary thrust bearing and planetary gear
(Fig. 145).
(3) Remove overrunning clutch assembly with
expanding type snap-ring pliers (Fig. 146). Insert pli-
ers into clutch hub. Expand pliers to grip hub splines
and remove clutch with counterclockwise, twisting
motion.
(4) Remove thrust bearing from overrunning
clutch hub.
(5) Remove overrunning clutch from hub.(6) Mark position of annulus gear and direct clutch
drum for assembly alignment reference (Fig. 147).
Use small center punch or scriber to make alignment
marks.
(7) Remove direct clutch drum rear retaining ring
(Fig. 148).
Fig. 146 Overrunning Clutch Assembly Removal/
Installation
1 - OVERRUNNING CLUTCH
2 - NEEDLE BEARING
Fig. 148 Clutch Drum Inner Retaining Ring Removal
1 - INNER RETAINING RING
2 - DIRECT CLUTCH DRUM
3 - ANNULUS GEAR
Fig. 145 Removing Sun Gear, Thrust Bearing And
Planetary Gear
1 - PLANETARY GEAR
2 - PLANETARY THRUST BEARING
3 - CLUTCH SPRING PLATE
4 - SPRING PLATE SNAP-RING
5 - SUN GEAR
Fig. 147 Marking Direct Clutch Drum And Annulus
Gear For Assembly Alignment
1 - DIRECT CLUTCH DRUM
2 - HAMMER
3 - PUNCH
21 - 404 AUTOMATIC TRANSMISSION - 48REDR
OVERDRIVE UNIT (Continued)

(8) Remove direct clutch drum outer retaining ring
(Fig. 149).
(9) Mark annulus gear and output shaft for assem-
bly alignment reference (Fig. 150). Use punch or
scriber to mark gear and shaft.
(10) Remove snap-ring that secures annulus gear
on output shaft (Fig. 151). Use two screwdrivers to
unseat and work snap-ring out of groove as shown.
(11) Remove annulus gear from output shaft (Fig.
152). Use rawhide or plastic mallet to tap gear off
shaft.
GEAR CASE AND PARK LOCK
(1) Remove locating ring from gear case.(2) Remove park pawl shaft retaining bolt and
remove shaft, pawl and spring.
(3) Remove reaction plug snap-ring and remove
reaction plug.
(4) Remove output shaft seal.
CLEANING
Clean the geartrain and case components with sol-
vent. Dry all parts except the bearings with com-
pressed air. Allow bearings to air dry.
Do not use shop towels for wiping parts dry unless
the towels are made from a lint-free material. A suffi-
cient quantity of lint (from shop towels, cloths, rags,
etc.) could plug the transmission filter and fluid pas-
sages.
Discard the old case gasket and seals. Do not
attempt to salvage these parts. They are not reus-
Fig. 149 Clutch Drum Outer Retaining Ring Removal
1 - OUTER RETAINING RING
Fig. 150 Marking Annulus Gear And Output Shaft
For Assembly Alignment
1 - OUTPUT SHAFT
2 - HAMMER
3 - PUNCH
Fig. 151 Annulus Gear Snap-Ring Removal
1 - OUTPUT SHAFT
2 - ANNULUS GEAR
3 - SNAP-RING
Fig. 152 Annulus Gear Removal
1 - OUTPUT SHAFT
2 - ANNULUS GEAR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 405
OVERDRIVE UNIT (Continued)

able. Replace any of the overdrive unit snap-rings if
distorted or damaged.
Minor nicks or scratches on components can be
smoothed with crocus cloth. However, do not attempt
to reduce severe scoring on any components with
abrasive materials. Replace severely scored compo-
nents; do not try to salvage them.
INSPECTION
Check condition of the park lock components and
the overdrive case.
Check the bushings in the overdrive case. Replace
the bushings if severely scored or worn. Also replace
the case seal if loose, distorted, or damaged.
Examine the overdrive and direct clutch discs and
plates. Replace the discs if the facing is worn,
severely scored, or burned and flaking off. Replace
the clutch plates if worn, heavily scored, or cracked.
Check the lugs on the clutch plates for wear. The
plates should slide freely in the drum. Replace the
plates or drum if binding occurs.
Check condition of the annulus gear, direct clutch
hub, clutch drum and clutch spring. Replace the gear,
hub and drum if worn or damaged. Replace the
spring if collapsed, distorted, or cracked.
Be sure the splines and lugs on the gear, drum and
hub are in good condition. The clutch plates and
discs should slide freely in these components.
Inspect the thrust bearings and spring plate.
Replace the plate if worn or scored. Replace the bear-
ings if rough, noisy, brinnelled, or worn.
Inspect the planetary gear assembly and the sun
gear and bushings. If either the sun gear or the
bushings are damaged, replace the gear and bush-
ings as an assembly. The gear and bushings are not
serviced separately.
The planetary carrier and pinions must be in good
condition. Also be sure the pinion pins are secure and in
good condition. Replace the carrier if worn or damaged.
Inspect the overrunning clutch and race. The race
surface should be smooth and free of scores. Replace
the overrunning clutch assembly or the race if either
assembly is worn or damaged in any way.
Replace the shaft pilot bushing and inner bushing
if damaged. Replace either shaft bearing if rough or
noisy. Replace the bearing snap-rings if distorted or
cracked.
Check the machined surfaces on the output shaft.
These surfaces should clean and smooth. Very minor
nicks or scratches can be smoothed with crocus cloth.
Replace the shaft if worn, scored or damaged in any way.
Inspect the output shaft bushings. The small bush-
ing is the intermediate shaft pilot bushing. The large
bushing is the overrunning clutch hub bushing.
Replace either bushing if scored, pitted, cracked, or
worn.
ASSEMBLY
GEARTRAIN AND DIRECT CLUTCH
(1) Soak direct clutch and overdrive clutch discs in
MopartATF +4, Automatic Transmission fluid. Allow
discs to soak for 10-20 minutes.
(2) Install annulus gear on output shaft, if
removed. Then install annulus gear retaining snap-
ring (Fig. 153).
(3) Align and install clutch drum on annulus gear
(Fig. 154). Be sure drum is engaged in annulus gear
lugs.
(4) Install clutch drum outer retaining ring (Fig.
154).
Fig. 153 Annulus Gear Installation
1 - SNAP-RING
2 - OUTPUT SHAFT FRONT BEARING
3 - ANNULUS GEAR
Fig. 154 Clutch Drum And Outer Retaining Ring
Installation
1 - ANNULUS GEAR
2 - OUTER SNAP-RING
3 - CLUTCH DRUM
21 - 406 AUTOMATIC TRANSMISSION - 48REDR
OVERDRIVE UNIT (Continued)

(5) Slide clutch drum forward and install inner
retaining ring (Fig. 155).
(6) Install rear bearing and snap-ring on output
shaft (Fig. 156). Be sure locating ring groove in bear-
ing is toward rear.
(7) Install overrunning clutch on hub (Fig. 157).
Note that clutch only fits one way. Shoulder on clutch
should seat in small recess at edge of hub.
(8) Install thrust bearing on overrunning clutch
hub. Use generous amount of petroleum jelly to hold
bearing in place for installation. Bearing fits one way
only. Be sure bearing is seated squarely against hub.
Reinstall bearing if it does not seat squarely.
(9) Install overrunning clutch in output shaft (Fig.
158). Insert snap-ring pliers in hub splines. Expand
pliers to grip hub. Then install assembly with coun-
terclockwise, twisting motion.
Fig. 158 Overrunning Clutch Installation
1 - CLUTCH DRUM
2 - OVERRUNNING CLUTCH ASSEMBLY
3 - EXPANDING-TYPE SNAP-RING PLIERS
4 - CLUTCH DRUM
5 - ANNULUS GEAR
6 - OVERRUNNING CLUTCH ASSEMBLY SEATED IN OUTPUT
SHAFT
Fig. 155 Clutch Drum Inner Retaining Ring
Installation
1 - ANNULUS GEAR
2 - INNER SNAP-RING
3 - CLUTCH DRUM
Fig. 156 Rear Bearing And Snap-Ring Installation
1 - REAR BEARING
2 - SNAP-RING
Fig. 157 Assembling Overrunning Clutch And Hub
1 - CLUTCH HUB
2 - OVERRUNNING CLUTCH
DRAUTOMATIC TRANSMISSION - 48RE 21 - 407
OVERDRIVE UNIT (Continued)