
AUTOMATIC TRANSMISSION - 42RE
TABLE OF CONTENTS
page page
AUTOMATIC TRANSMISSION - 42RE
DESCRIPTION..........................135
OPERATION............................137
DIAGNOSIS AND TESTING................143
AUTOMATIC TRANSMISSION.............143
PRELIMINARY........................143
ROAD TESTING.......................143
HYDRAULIC PRESSURE TEST...........144
AIR CHECKING TRANSMISSION CLUTCH
AND BAND OPERATION.................147
CONVERTER HOUSING FLUID LEAK......148
DIAGNOSIS CHARTS...................149
STANDARD PROCEDURE.................159
ALUMINUM THREAD REPAIR.............159
REMOVAL.............................159
DISASSEMBLY..........................160
CLEANING.............................165
INSPECTION...........................165
ASSEMBLY............................166
INSTALLATION..........................173
SCHEMATICS AND DIAGRAMS.............174
SPECIFICATIONS........................186
SPECIAL TOOLS........................188
ACCUMULATOR
DESCRIPTION..........................191
OPERATION............................191
INSPECTION...........................192
BANDS
DESCRIPTION..........................192
OPERATION............................192
ADJUSTMENTS.........................193
ELECTRONIC GOVERNOR
DESCRIPTION..........................194
OPERATION............................194
REMOVAL.............................196
INSTALLATION..........................197
EXTENSION HOUSING BUSHING
REMOVAL.............................198
INSTALLATION..........................198
EXTENSION HOUSING SEAL
REMOVAL.............................198
INSTALLATION..........................198
FLUID AND FILTER
DIAGNOSIS AND TESTING................199
EFFECTS OF INCORRECT FLUID LEVEL . . . 199
CAUSES OF BURNT FLUID..............199
FLUID CONTAMINATION................199
STANDARD PROCEDURE.................199
FLUID LEVEL CHECK...................199FLUID AND FILTER REPLACEMENT.......201
TRANSMISSION FILL...................201
FRONT CLUTCH
DESCRIPTION..........................202
OPERATION............................202
DISASSEMBLY..........................202
INSPECTION...........................205
ASSEMBLY............................206
FRONT SERVO
DESCRIPTION..........................206
OPERATION............................207
DISASSEMBLY..........................207
CLEANING.............................207
INSPECTION...........................207
ASSEMBLY............................208
OIL PUMP
DESCRIPTION..........................208
OPERATION............................208
STANDARD PROCEDURE.................209
OIL PUMP VOLUME CHECK..............209
DISASSEMBLY..........................209
CLEANING.............................211
INSPECTION...........................211
ASSEMBLY............................212
OUTPUT SHAFT FRONT BEARING
REMOVAL.............................213
INSTALLATION..........................213
OUTPUT SHAFT REAR BEARING
REMOVAL.............................213
INSTALLATION..........................213
OVERDRIVE CLUTCH
DESCRIPTION..........................214
OPERATION............................214
OVERDRIVE OFF SWITCH
DESCRIPTION..........................215
OPERATION............................215
DIAGNOSIS AND TESTING................215
OVERDRIVE ELECTRICAL CONTROLS.....215
REMOVAL.............................215
INSTALLATION..........................215
OVERDRIVE UNIT
REMOVAL.............................216
DISASSEMBLY..........................217
CLEANING.............................224
INSPECTION...........................224
ASSEMBLY............................225
INSTALLATION..........................234
21 - 134 AUTOMATIC TRANSMISSION - 42REBR/BE

FOURTH GEAR POWERFLOW
Fourth gear overdrive range is electronically con-
trolled and hydraulically activated. Various sensor
inputs are supplied to the powertrain control module
to operate the overdrive solenoid on the valve body.
The solenoid contains a check ball that opens and
closes a vent port in the 3-4 shift valve feed passage.
The overdrive solenoid (and check ball) are not ener-
gized in first, second, third, or reverse gear. The vent
port remains open, diverting line pressure from the
2-3 shift valve away from the 3-4 shift valve. The
overdrive control switch must be in the ON position
to transmit overdrive status to the PCM. A 3-4
upshift occurs only when the overdrive solenoid is
energized by the PCM. The PCM energizes the over-
drive solenoid during the 3-4 upshift. This causes the
solenoid check ball to close the vent port allowing
line pressure from the 2-3 shift valve to act directly
on the 3-4 upshift valve. Line pressure on the 3-4
shift valve overcomes valve spring pressure moving
the valve to the upshift position. This action exposes
the feed passages to the 3-4 timing valve, 3-4 quick
fill valve, 3-4 accumulator, and ultimately to the
overdrive piston. Line pressure through the timing
valve moves the overdrive piston into contact with
the overdrive clutch. The direct clutch is disengaged
before the overdrive clutch is engaged. The boost
valve provides increased fluid apply pressure to the
overdrive clutch during 3-4 upshifts, and when accel-
erating in fourth gear. The 3-4 accumulator cushions
overdrive clutch engagement to smooth 3-4 upshifts.
The accumulator is charged at the same time as
apply pressure acts against the overdrive piston.
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION
Automatic transmission problems can be a result of
poor engine performance, incorrect fluid level, incor-
rect linkage or cable adjustment, band or hydraulic
control pressure adjustments, hydraulic system mal-
functions or electrical/mechanical component mal-
functions. Begin diagnosis by checking the easily
accessible items such as: fluid level and condition,
linkage adjustments and electrical connections. A
road test will determine if further diagnosis is neces-
sary.
DIAGNOSIS AND TESTING - PRELIMINARY
Two basic procedures are required. One procedure
for vehicles that are drivable and an alternate proce-
dure for disabled vehicles (will not back up or move
forward).
VEHICLE IS DRIVEABLE
(1) Check for transmission fault codes using DRBt
scan tool.(2) Check fluid level and condition.
(3) Adjust throttle and gearshift linkage if com-
plaint was based on delayed, erratic, or harsh shifts.
(4) Road test and note how transmission upshifts,
downshifts, and engages.
(5) Perform hydraulic pressure test if shift prob-
lems were noted during road test.
(6) Perform air-pressure test to check clutch-band
operation.
VEHICLE IS DISABLED
(1) Check fluid level and condition.
(2) Check for broken or disconnected gearshift or
throttle linkage.
(3) Check for cracked, leaking cooler lines, or loose
or missing pressure-port plugs.
(4) Raise and support vehicle on safety stands,
start engine, shift transmission into gear, and note
following:
(a) If propeller shaft turns but wheels do not,
problem is with differential or axle shafts.
(b) If propeller shaft does not turn and transmis-
sion is noisy, stop engine. Remove oil pan, and
check for debris. If pan is clear, remove transmis-
sion and check for damaged drive plate, converter,
oil pump, or input shaft.
(c) If propeller shaft does not turn and transmis-
sion is not noisy, perform hydraulic-pressure test to
determine if problem is hydraulic or mechanical.
DIAGNOSIS AND TESTING - ROAD TESTING
Before road testing, be sure the fluid level and con-
trol cable adjustments have been checked and
adjusted if necessary. Verify that diagnostic trouble
codes have been resolved.
Observe engine performance during the road test.
A poorly tuned engine will not allow accurate analy-
sis of transmission operation.
Operate the transmission in all gear ranges. Check
for shift variations and engine flare which indicates
slippage. Note if shifts are harsh, spongy, delayed,
early, or if part throttle downshifts are sensitive.
Slippage indicated by engine flare, usually means
clutch, band or overrunning clutch problems. If the
condition is advanced, an overhaul will be necessary
to restore normal operation.
A slipping clutch or band can often be determined
by comparing which internal units are applied in the
various gear ranges. The Clutch and Band Applica-
tion chart provides a basis for analyzing road test
results.
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 143
AUTOMATIC TRANSMISSION - 42RE (Continued)

PRESSURE TEST ANALYSIS CHART
TEST CONDITION INDICATION
Line pressure OK during
any one testPump and regulator
valve OK
Line pressure OK in R
but low in D, 2, 1Leakage in rear clutch
area (seal rings, clutch
seals)
Pressure low in D Fourth
Gear RangeOverdrive clutch piston
seal, or check ball
problem
Pressure OK in 1, 2 but
low in D3 and RLeakage in front clutch
area
Pressure OK in 2 but low
in R and 1Leakage in rear servo
Front servo pressure in 2 Leakage in servo; broken
servo ring or cracked
servo piston
Pressure low in all
positionsClogged filter, stuck
regulator valve, worn or
faulty pump, low oil level
Governor pressure too
high at idle speedGovernor pressure
solenoid valve system
fault. Refer to diagnostic
book.
Governor pressure low at
all mph figuresFaulty governor pressure
solenoid, transmission
control module, or
governor pressure
sensor
Lubrication pressure low
at all throttle positionsClogged fluid cooler or
lines, seal rings leaking,
worn pump bushings,
pump, clutch retainer, or
clogged filter.
Line pressure high Output shaft plugged,
sticky regulator valve
Line pressure low Sticky regulator valve,
clogged filter, worn pump
DIAGNOSIS AND TESTING - AIR CHECKING
TRANSMISSION CLUTCH AND BAND
OPERATION
Air-pressure testing can be used to check transmis-
sion front/rear clutch and band operation. The test
can be conducted with the transmission either in the
vehicle or on the work bench, as a final check, after
overhaul.
Air-pressure testing requires that the oil pan and
valve body be removed from the transmission. The
servo and clutch apply passages are shown (Fig. 10).
Front Clutch Air Test
Place one or two fingers on the clutch housing and
apply air pressure through front clutch apply pas-
sage. Piston movement can be felt and a soft thump
heard as the clutch applies.
Rear Clutch Air Test
Place one or two fingers on the clutch housing and
apply air pressure through rear clutch apply passage.
Fig. 10 Air Pressure Test Passages
1 - REAR SERVO APPLY
2 - FRONT SERVO APPLY
3 - PUMP SUCTION
4 - FRONT CLUTCH APPLY
5 - FRONT SERVO RELEASE
6 - LINE PRESSURE TO ACCUMULATOR
7 - PUMP PRESSURE
8 - TO CONVERTER
9 - REAR CLUTCH APPLY
10 - FROM CONVERTER
11 - TO COOLER
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 147
AUTOMATIC TRANSMISSION - 42RE (Continued)

ELINE/PROPELLER SHAFT/PROPELLER SHAFT -
REMOVAL)
(12) Disconnect wires from park/neutral position
switch and transmission solenoid.
(13) Disconnect gearshift rod and torque shaft
assembly from transmission.
(14) Disconnect throttle valve cable from transmis-
sion bracket and throttle valve lever.
(15) On4x4models, disconnect shift rod from
transfer case shift lever.
(16)
Support rear of engine with safety stand or jack.
(17) Raise transmission slightly with service jack
to relieve load on crossmember and supports.
(18) Remove bolts securing rear support and cush-
ion to transmission and crossmember. Raise trans-
mission slightly, slide exhaust hanger arm from
bracket (Fig. 15) and remove rear support.
(19) Remove bolts attaching crossmember to frame
and remove crossmember.
(20) On4x4models, remove transfer case with
transmission jack or aid of helper.
(21) Remove all converter housing bolts.
(22) Carefully work transmission and torque con-
verter assembly rearward off engine block dowels.
(23) Lower transmission and remove assembly
from under the vehicle.
(24) To remove torque converter, remove C-clamp
from edge of bell housing and carefully slide torque
converter out of the transmission.
DISASSEMBLY
(1) Clean transmission exterior with steam gun or
with solvent. Wear eye protection during cleaning
operations.
(2) Place transmission in a vertical position.(3)
Measure input shaft end play as follows (Fig. 16).
(a) Attach Adapter 8266-6 to Handle 8266-8.
(b) Attach dial indicator C-3339 to Handle
8266-8.
(c)
Install the assembled tool onto the input shaft
of the transmission and tighten the retaining screw
on Adapter 8266-6 to secure it to the input shaft.
(d)Position the dial indicator plunger against a
flat spot on the oil pump and zero the dial indicator.
(e) Move the input shaft in and out. Record the
maximum travel for assembly reference.
Fig. 14 Fill Tube Attachment
1 - TRANSFER CASE VENT TUBE
2 - FILL TUBE (V8)
3 - TUBE SEAL
4 - FILL TUBE (V6)Fig. 15 Rear Support Cushion
1 - EXHAUST PIPE ARM AND BRACKET
2 - CROSSMEMBER
3 - REAR SUPPORT AND CUSHION
Fig. 16 Checking Input Shaft End Play
1 - TOOL 8266-8
2 - TOOL 8266-6
3 - TOOL C-3339
21 - 160 AUTOMATIC TRANSMISSION - 42REBR/BE
AUTOMATIC TRANSMISSION - 42RE (Continued)

(a) Align and carefully insert park rod into pawl.
Rod will make click noise as it enters pawl. Move
rod slightly to check engagement.
(b) Align and seat valve body on case. Be sure
manual lever shaft and overdrive connector are
fully seated in case. Also be sure valve body wiring
is not pinched or kinked.
(c) Install and start all valve body attaching
bolts by hand. Then tighten bolts evenly, in a diag-
onal pattern to 12 N´m (105 in. lbs.) torque. Do not
overtighten valve body bolts. This could result in
distortion and cross leakage after installation.
CAUTION: It is possible for the park rod to displace
into a cavity just above the pawl sprag during
installation. Make sure the rod is actually engaged
in the pawl and has not displaced into the cavity.
(33) Install new filter on valve body. Tighten filter
screws to 4 N´m (35 in. lbs.).
(34) Adjust front and rear bands.
(35) Install seal on park/neutral position switch.
Then install and tighten switch to 34 N´m (25 ft.
lbs.).
(36) Install magnet in oil pan. Magnet goes on
small protrusion at corner of pan.
(37) Position new oil pan gasket on case and
install oil pan. Tighten pan bolts to 17 N´m (13 ft.
lbs.).
(38) Install new valve body manual shaft seal in
case (Fig. 55). Lubricate seal lip and manual shaft
with petroleum jelly. Start seal over shaft and into
case. Seat seal with 15/16 inch, deep well socket.
(39) Install throttle valve and shift selector levers
on valve body manual lever shaft.
Fig. 53 Checking Input Shaft End Play
1 - TOOL 8266-8
2 - TOOL 8266-6
3 - TOOL C-3339
Fig. 54 Accumulator Piston And Springs
1 - GOVERNOR PRESSURE SENSOR
2 - VALVE BODY
3 - PARK ROD
4 - ACCUMULATOR PISTON
5 - GOVERNOR PRESSURE SOLENOID
Fig. 55 Installing Manual Lever Shaft Seal
1 - 15/16©© SOCKET
2 - SEAL
21 - 172 AUTOMATIC TRANSMISSION - 42REBR/BE
AUTOMATIC TRANSMISSION - 42RE (Continued)

INSTALLATION
(1) Check torque converter hub and hub drive
notches for sharp edges burrs, scratches, or nicks.
Polish the hub and notches with 320/400 grit paper
and crocus cloth if necessary. The hub must be
smooth to avoid damaging pump seal at installation.
(2) Lubricate pocket in the rear oil pump seal lip
with transmission fluid.
(3) Lubricate converter pilot hub of the crankshaft
with a light coating of MopartHigh Temp Grease.
(4) Align and install converter in oil pump.
(5) Carefully insert converter in oil pump. Then
rotate converter back and forth until fully seated in
pump gears.
(6) Check converter seating with steel scale and
straightedge (Fig. 56). Surface of converter lugs
should be 1/2 in. to rear of straightedge when con-
verter is fully seated.
(7) Temporarily secure converter with C-clamp.
(8) Position transmission on jack and secure it
with chains.
(9) Check condition of converter driveplate.
Replace the plate if cracked, distorted or damaged.
Also be sure transmission dowel pins are seated
in engine block and protrude far enough to
hold transmission in alignment.
(10) Raise transmission and align converter with
drive plate and converter housing with engine block.
(11) Move transmission forward. Then raise, lower
or tilt transmission to align converter housing with
engine block dowels.(12) Carefully work transmission forward and over
engine block dowels until converter hub is seated in
crankshaft.
(13) Install bolts attaching converter housing to
engine.
(14) Install rear support. Then lower transmission
onto crossmember and install bolts attaching trans-
mission mount to crossmember.
(15) Remove engine support fixture.
(16) Install crankshaft position sensor. (Refer to 14
- FUEL SYSTEM/FUEL INJECTION/CRANKSHAFT
POSITION SENSOR - INSTALLATION)
(17) Install new plastic retainer grommet on any
shift linkage rod or lever that was disconnected.
Grommets should not be reused. Use pry tool to
remove rod from grommet and cut away old grom-
met. Use pliers to snap new grommet into lever and
to snap rod into grommet at assembly.
(18) Connect gearshift and throttle cable to trans-
mission.
(19) Connect wires to park/neutral position switch,
transmission solenoid(s) and oxygen sensor. Be sure
transmission harnesses are properly routed.
CAUTION: It is essential that correct length bolts be
used to attach the converter to the driveplate. Bolts
that are too long will damage the clutch surface
inside the converter.
(20) Install torque converter-to-driveplate bolts.
On models with 10.75 in. converter, tighten bolts to
31 N´m (270 in. lbs.). On models with 12.2 in. con-
verter, tighten bolts to 47 N´m (35 ft. lbs.).
(21) Install converter housing access cover.
(22) Install starter motor and cooler line bracket.
(Refer to 8 - ELECTRICAL/STARTING/STARTER
MOTOR - INSTALLATION)
(23) Connect cooler lines to transmission.
(24) Install transmission fill tube. Install new seal
on tube before installation.
(25) Install exhaust components.
(26) Align and connect propeller shaft. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - INSTALLATION)
(27) Adjust gearshift linkage and throttle valve
cable if necessary.
(28) Lower vehicle.
(29) Fill transmission with MopartATF +4, type
9602, Automatic Transmission fluid.
Fig. 56 Checking Converter Seating - Typical
1 - SCALE
2 - STRAIGHTEDGE
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 173
AUTOMATIC TRANSMISSION - 42RE (Continued)

FLUID AND FILTER
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has two primary causes.
(1) A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged main cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
(2) Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²
overheat that generates sludge (fluid breakdown)
²failure to reverse flush cooler and lines after repair
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failure
due to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped clean
before checking fluid level. Dirt, grease and other for-
eign material on the cap and tube could fall into the
tube if not removed beforehand. Take the time to wipe
the cap and tube clean before withdrawing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The transmission cooler and lines should be
reverse flushed whenever a malfunction generates
sludge and/or debris. The torque converter should
also be replaced at the same time.
Failure to flush the cooler and lines will result in
recontamination. Flushing applies to auxiliary coolers
as well. The torque converter should also be replaced
whenever a failure generates sludge and debris. This is
necessary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can inter-
fere with normal valve, clutch, and accumulator opera-
tion. Foaming can also result in fluid escaping from the
transmission vent where it may be mistaken for a leak.
Along with fluid level, it is important to check the
condition of the fluid. When the fluid smells burned,
and is contaminated with metal or friction material
particles, a complete transmission recondition is
needed. Be sure to examine the fluid on the dipstick
closely. If there is any doubt about its condition,
drain out a sample for a double check.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
Fluid level is checked with the engine running at curb
idle speed, the transmission in NEUTRAL and the trans-
mission fluid at normal operating temperature.The
engine should be running at idle speed for at least
one minute, with the vehicle on level ground.
The transmission fluid level can be checked two
ways.
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 199

PROCEDURE ONE
(1) Transmission fluid must be at normal operat-
ing temperature for accurate fluid level check. Drive
vehicle if necessary to bring fluid temperature up to
normal hot operating temperature of 82ÉC (180ÉF).
(2) Position vehicle on level surface.
(3) Start and run engine at curb idle speed.
(4) Apply parking brakes.
(5) Shift transmission momentarily into all gear
ranges. Then shift transmission back to NEUTRAL.
(6) Clean top of filler tube and dipstick to keep
dirt from entering tube.
(7) Remove dipstick (Fig. 80) and check fluid level
as follows:
(a) Correct acceptable level is in crosshatch area.
(b) Correct maximum level is to MAX arrow
mark.
(c) Incorrect level is at or below MIN line.
(d) If fluid is low, add only enough MopartAT F
+4, type 9602, to restore correct level. Do not over-
fill.
PROCEDURE TWO
(1) Start engine and apply parking brake.
(2) Shift the transmission into DRIVE for approxi-
mately 2 seconds.
(3) Shift the transmission into REVERSE for
approximately 2 seconds.
(4) Shift the transmission into PARK.(5) Hook up DRBtscan tool and select engine.
(6) Select sensors.
(7) Read the transmission temperature value.
(8) Compare the fluid temperature value with the
figure. (Fig. 81)
(9) Adjust transmission fluid level shown on the
dipstick according to the figure.
NOTE: After adding any fluid to the transmission,
wait a minimum of 2 minutes for the oil to fully
drain from the fill tube into the transmission before
rechecking the fluid level.
(10) Check transmission for leaks.
Fig. 80 Dipstick Fluid Level Marks - Typical
1 - DIPSTICK
2 - MAXIMUM CORRECT FLUID LEVEL
3 - ACCEPTABLE FLUID LEVEL
Fig. 81 42/44RE Fluid Fill Graph
21 - 200 AUTOMATIC TRANSMISSION - 42REBR/BE
FLUID AND FILTER (Continued)