CONDITION POSSIBLE CAUSES CORRECTION
OIL LEAKS. 1. Fluid Lines and Fittings Loose/
Leaks/Damaged.1. Tighten fittings. If leaks persist, replace
fittings and lines if necessary.
2. Fill Tube (where tube enters case)
Leaks/Damaged.2. Replace tube seal. Inspect tube for
cracks in fill tube.
3. Pressure Port Plug Loose
Loose/Damaged.3. Tighten to correct torque. Replace plug
or reseal if leak persists.
4. Pan Gasket Leaks. 4. Tighten pan screws (150 in. lbs.). If leaks
persist, replace gasket.
5. Valve Body Manual Lever Shaft
Seal Leaks/Worn.5. Replace shaft seal.
6. Rear Bearing Access Plate Leaks. 6. Replace gasket. Tighten screws.
7. Gasket Damaged or Bolts are
Loose.7. Replace bolts or gasket or tighten both.
8. Adapter/Extension Gasket
Damaged Leaks/Damaged.8. Replace gasket.
9. Park/Neutral Switch, or
Transmission Range Sensor
Leaks/Damaged.9. Replace switch and gasket.
10. Converter Housing Area Leaks. 10. Check for leaks at seal caused by worn
seal or burr on converter hub (cutting seal),
worn bushing, missing oil return, oil in front
pump housing or hole plugged. Check for
leaks past O-ring seal on pump or past
pump-to-case bolts; pump housing porous,
oil coming out vent due to overfill or leak
past front band shaft access plug.
11. Pump Seal Leaks/Worn/
Damaged.11. Replace seal.
12. Torque Converter Weld
Leak/Cracked Hub.12. Replace converter.
13. Case Porosity Leaks. 13. Replace case.
NOISY OPERATION IN
FOURTH GEAR ONLY1. Overdrive Clutch Discs, Plates or
Snap Rings Damaged.1. Remove unit and rebuild clutch pack.
2. Overdrive Piston or Planetary
Thrust Bearing Damaged.2. Remove and disassemble unit. Replace
either thrust bearing if damaged.
3. Output Shaft Bearings Scored/
Damaged.3. Remove and disassemble unit. Replace
either bearing if damaged.
4. Planetary Gears Worn/Chipped. 4. Remove and overhaul overdrive unit.
5. Overdrive Unit Overrunning Clutch
Rollers Worn/Scored.5. Remove and overhaul overdrive unit.
DRAUTOMATIC TRANSMISSION - 48RE 21 - 157
AUTOMATIC TRANSMISSION - 48RE (Continued)
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR
Damaged or worn threads in the aluminum trans-
mission case and valve body can be repaired by the
use of Heli-CoilsŸ, or equivalent. This repair con-
sists of drilling out the worn-out damaged threads.
Then tap the hole with a special Heli-CoilŸ tap, or
equivalent, and installing a Heli-CoilŸ insert, or
equivalent, into the hole. This brings the hole back to
its original thread size.
Heli-CoilŸ, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
REMOVAL
NOTE: The overdrive unit can be removed and ser-
viced separately. It is not necessary to remove the
entire transmission assembly to perform overdrive
unit repairs.
(1) Disconnect battery negative cable.
(2) Raise vehicle.
(3) Remove the transfer case skid plate (Fig. 12), if
equipped.(4) Disconnect and lower or remove necessary
exhaust components.
(5) Remove engine-to-transmission struts.
(6) Remove starter motor. (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL)
(7) Disconnect and remove the crankshaft position
sensor. (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION/CRANKSHAFT POSITION SENSOR -
REMOVAL) Retain the sensor attaching bolts.
(8) If transmission is being removed for overhaul,
remove transmission oil pan, drain fluid and reinstall
pan.
(9) Remove torque converter access cover.
(10) Rotate crankshaft in clockwise direction until
converter bolts are accessible. Then remove bolts one
at a time. Rotate crankshaft with socket wrench on
dampener bolt.
(11) Mark propeller shaft and axle yokes for
assembly alignment. Then disconnect and remove
propeller shaft. On4x4models, remove both propel-
ler shafts. (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE/PROPELLER SHAFT/PROPELLER SHAFT -
REMOVAL)
(12) Disconnect wires from the transmission range
sensor and transmission solenoid connector.
(13) Disconnect gearshift cable (Fig. 13) from the
transmission.
Fig. 12 Transfer Case Skid Plate
1 - FRAME RAIL
2 - SKID PLATE
3 - BOLTS (6)
Fig. 13 Gearshift Cable At Transmission
1 - GEARSHIFT CABLE
2 - TRANSMISSION MANUAL LEVER
3 - CABLE SUPPORT BRACKET
21 - 158 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
DISASSEMBLY
(1) Clean exterior of transmission with suitable
solvent or pressure washer.
(2) Place transmission in vertical position.
(3) Measure the input shaft end play as follows
(Fig. 17).
(a) Attach Adapter 8266-5 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 8266-5 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 indica-
tor.
(e) Move input shaft in and out and record read-
ing. Record the maximum travel for assembly ref-
erence
(4) Remove the overdrive unit from the main
transmission case. If overdrive unit is not to be ser-
viced, install Alignment Shaft 6227-2 into the over-
drive unit to prevent misalignment of the overdrive
clutches during service of main transmission compo-
nents.
(5) Remove throttle and shift levers from valve
body manual shaft and throttle lever shaft.
(6) Remove transmission oil pan and gasket.(7) Remove filter from valve body (Fig. 18). Keep
filter screws separate from other valve body screws.
Filter screws are longer and should be kept with fil-
ter.
(8) Remove the transmission range sensor.
(9) Remove hex head bolts attaching valve body to
transmission case (Fig. 19). A total of 10 bolts are
used. Note different bolt lengths for assembly refer-
ence.
Fig. 19 Valve Body Bolt Locations
1 - VALVE BODY BOLTS
2 - VALVE BODY BOLTS
Fig. 17 Checking Input Shaft End Play
1 - TOOL 8266-8
2 - TOOL 8266-5
3 - TOOL C-3339
Fig. 18 Oil Filter Removal
1 - OIL FILTER
2 - VALVE BODY
3 - FILTER SCREWS (2)
21 - 160 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
(10) Remove valve body assembly. Push valve body
harness connector out of case. Then work park rod
and valve body out of case (Fig. 20).
(11) Remove accumulator outer spring, piston and
inner spring (Fig. 21). Note position of piston and
springs for assembly reference. Remove and discard
piston seals if worn or cut.
(12) Remove pump oil seal with suitable pry tool
or slide-hammer mounted screw.
(13) Remove front band lever pin access plug (Fig.
22). Use square end of 1/4 in. drive extension to
remove plug as shown.(14) Remove oil pump and reaction shaft support
assembly as follows:
(a) Tighten front band adjusting screw until
band is tight around front clutch retainer (Fig. 23).
This will prevent retainer from coming out with
pump and possibly damaging clutch or pump com-
ponents.
Fig. 23 Tightening Front Band To Hold Front Clutch
In Place
1 - LOCK-NUT
2 - FRONT BAND ADJUSTER
Fig. 20 Valve Body Removal
1 - GOVERNOR PRESSURE SENSOR
2 - VALVE BODY
3 - PARK ROD
4 - ACCUMULATOR PISTON
5 - GOVERNOR PRESSURE SOLENOID
Fig. 21 Accumulator Component Removal
1 - ACCUMULATOR PISTON
2 - OUTER SPRING
3 - INNER SPRING
Fig. 22 Front Band Lever Pin Access Plug
1 - FRONT BAND REACTION PIN ACCESS PLUG
2 - 1/4 DRIVE EXTENSION AND RATCHET
DRAUTOMATIC TRANSMISSION - 48RE 21 - 161
AUTOMATIC TRANSMISSION - 48RE (Continued)
(22) Remove thrust plate from intermediate shaft
hub (Fig. 32).
(23) Remove intermediate shaft-planetary
geartrain assembly (Fig. 33).
(24) Loosen rear band locknut and loosen adjust-
ing screw 3-4 turns.
(25) Remove snap-ring that retains low-reverse
drum on overdrive piston retainer hub (Fig. 34).
(26) Slide low-reverse drum and thrust washer off
piston retainer hub and out of rear band (Fig. 35).
Fig. 35 Low-Reverse Drum And Thrust Washer
1 - LOW-REVERSE DRUM
2 - SPOTFACE FOR WASHER
3 - THRUST WASHER
Fig. 32 Intermediate Shaft Thrust Plate
1 - SHAFT THRUST PLATE
2 - INTERMEDIATE SHAFT PILOT HUB
Fig. 33 Intermediate Shaft And Planetary Geartrain
1 - INTERMEDIATE SHAFT AND PLANETARY GEAR TRAIN
ASSEMBLY
Fig. 34 Low-Reverse Drum Snap-Ring
1 - LOW-REVERSE DRUM
2 - TABBED WASHER
3 - SNAP-RING
21 - 164 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
(7) Bottom front servo piston in bore and install
servo spring.
(8) Install front servo piston rod guide as follows:
(a) Place Tool SP-5560 (or similar size tool) on
guide and position C-clamp on tool and case (Fig.
44).
(b) Slowly compress rod guide while simulta-
neously easing seal ring into bore with suitable
tool.
(9) Install rod guide snap-ring (Fig. 44).
OVERRUNNING CLUTCH, REAR BAND, AND
LOW-REVERSE DRUM
(1) Install overrunning clutch components if not
yet installed.
(2) Position rear band reaction pin and band in
case. Be sure that the twin lugs on the band are
seated against the reaction pin.
(3) Install low-reverse drum. Slide drum through
rear band, onto piston retainer hub and into engage-
ment with overrunning clutch and race.
(4) Install thrust washer in low-reverse drum spot-
face (Fig. 45). Use petroleum jelly to hold washer in
place.
(5) Install snap-ring that secures low-reverse drum
to piston retainer hub (Fig. 45).
(6) Insert the rear band pivot pin part way into
the case.(7) Install rear band adjusting lever and pivot pin.
Be sure lever and the single lug on the band are
aligned and engaged before seating band pivot pin in
case.
Fig. 43 Front Servo Piston
1 - USE SUITABLE TOOL TO HELP SEAT PISTON RING
2 - FRONT SERVO PISTON
Fig. 44 Front Servo Rod Guide And Snap Ring
1 - C-CLAMP
2 - ROD GUIDE
3 - SMALL SCREWDRIVER
4 - ROD GUIDE SNAP-RING
5 - TOOL SP-5560
Fig. 45 Low-Reverse Drum Snap Ring
1 - LOW-REVERSE DRUM
2 - TABBED WASHER
3 - SNAP-RING
21 - 168 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
(4) Check seal rings on reaction shaft support. Be
sure rings are hooked together correctly. Also be sure
fiber thrust washer is in position (Fig. 55). Use extra
petroleum jelly to hold washer in place if necessary.
(5) Check the torque converter hub seal ring on
the reaction shaft for damage. Also check that the
seal ring rotates freely in the reaction shaft groove.
Replace the seal if necessary.
(6) Lubricate oil pump seals with petroleum
MopartATF +4.
(7) Mount oil pump on pilot studs and slide pump
into case opening (Fig. 56).Work pump into case
by hand. Do not use a mallet or similar tools to
seat pump.
(8) Remove pilot studs and install oil pump bolts.
Tighten pump bolts alternately and evenly to fully
seat pump in case. Then final-tighten pump bolts to
20 N´m (15 ft. lbs.) torque.
(9) Verify correct installation. Rotate input and
intermediate shafts and check for bind. If bind exists,
components are either mis-assembled, or not seated.
Disassemble and correct as necessary before proceed-
ing.
INPUT SHAFT END PLAY CHECK
NOTE: Overdrive unit must be installed in order to
correctly measure the input shaft end-play.
(1) Measure input shaft end play (Fig. 57).NOTE: If end play is incorrect, transmission is
incorrectly assembled, or reaction shaft thrust
washer is incorrect. The reaction shaft thrust
washer is selective.
(a) Attach Adapter 8266-5 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 8266-5 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 indica-
tor.
(e) Move input shaft in and out and record read-
ing. End play should be 0.86 - 2.13 mm (0.034 -
0.084 in.). Adjust as necessary.
ACCUMULATOR, VALVE BODY, OIL PAN, AND
TORQUE CONVERTER
(1) Install accumulator inner spring, piston and
outer spring (Fig. 58).
(2) Verify that the transmission range sensor has
notbeen installed in case. Valve body can not be
installed if sensor is in position.
(3) Install new valve body manual shaft seal in
case (Fig. 59). 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.
(4) Install valve body as follows:Fig. 56 Oil Pump
1 - SEAT OIL PUMP IN CASE BY HAND
2 - REMOVE PILOT STUDS WHEN PUMP IS SEATED
Fig. 57 Checking Input Shaft End Play
1 - TOOL 8266-8
2 - TOOL 8266-5
3 - TOOL C-3339
21 - 172 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
(a) Start park rod into park pawl. If rod will not
slide past park pawl, pawl is engaged in park gear.
Rotate overdrive output shaft with suitable size 12
point socket; this will free pawl and allow rod to
engage.
(b) Align and seat valve body on case. Be sure
manual lever shaft and overdrive connector are
fully seated in case.
(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..
(5) Install new filter on valve body. Tighten filter
screws to 4 N´m (35 in. lbs.).
CAUTION: If the condition of the transmission
before the overhaul procedure caused excessive
metallic or fiber contamination in the fluid, replace
the torque converter and reverse flush the cooler(s)
and cooler lines. Fluid contamination and transmis-
sion failure can result if not done.(6) Move the transmission manual shaft lever to
the manual LOW position.
(7) Install the TRS mounting bracket into the
transmission case. Using Adapter 8581 (Fig. 60),
tighten the mounting bracket to 34 N´m (300 in.lbs.).
(8) Install the TRS (Fig. 61) into the mounting
bracket with the wiring connector facing the front of
the transmission.
Fig. 58 Accumulator Piston And Springs
1 - ACCUMULATOR PISTON
2 - OUTER SPRING
3 - INNER SPRING
Fig. 59 Manual Lever Shaft Seal
1 - 15/1688SOCKET
2 - SEAL
Fig. 60 Tighten the TRS Mounting Bracket
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - ADAPTER 8581
Fig. 61 Remove Transmission Range Sensor
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - TRANSMISSION RANGE SENSOR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 173
AUTOMATIC TRANSMISSION - 48RE (Continued)