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)
(33) Remove tools and remove servo piston and
spring.
(34) Compress rear servo piston with C-clamp and
Tool C-4470, or Valve Spring Compressor C-3422-B
(Fig. 39). Compress servo spring retainer only
enough to permit snap-ring removal.
(35) Remove servo piston snap-ring (Fig. 39). Start
one end of ring out of bore. Then carefully work
removal tool around back of snap-ring until free of
ring groove.Exercise caution when removing
snap-ring. Servo bore can be scratched or
nicked if care is not exercised.
(36) Remove tools and remove rear servo retainer,
spring and piston assembly.
CLEANING
Clean the case in a solvent tank. Flush the case
bores and fluid passages thoroughly with solvent.
Dry the case and all fluid passages with compressed
air. Be sure all solvent is removed from the case and
that all fluid passages are clear.
NOTE: Do not use shop towels or rags to dry the
case (or any other transmission component) unless
they are made from lint-free materials. Lint will stick
to case surfaces and transmission components and
circulate throughout the transmission after assem-
bly. A sufficient quantity of lint can block fluid pas-
sages and interfere with valve body operation.
Lubricate transmission parts with MopartATF +4,
Automatic Transmission fluid, during overhaul and
assembly. Use petroleum jelly to prelubricate seals,
O-rings, and thrust washers. Petroleum jelly can also
be used to hold parts in place during reassembly.
INSPECTION
Inspect the case for cracks, porous spots, worn
bores, or damaged threads. Damaged threads can be
repaired with Helicoil thread inserts. However, the
case will have to be replaced if it exhibits any type of
damage or wear.
Lubricate the front band adjusting screw threads
with petroleum jelly and thread the screw part-way
into the case. Be sure the screw turns freely.
Inspect the transmission bushings during overhaul.
Bushing condition is important as worn, scored bush-
ings contribute to low pressures, clutch slip and
accelerated wear of other components. However, do
not replace bushings as a matter of course. Replace
bushings only when they are actually worn, or
scored.
The use of crocus cloth is permissible where neces-
sary, providing it is used carefully. When used on
shafts, or valves, use extreme care to avoid rounding
off sharp edges. Sharp edges are vital as they pre-
vent foreign matter from getting between the valve
and valve bore.
Do not reuse oil seals, gaskets, seal rings, or
O-rings during overhaul. Replace these parts as a
matter of course. Also do not reuse snap rings or
E-clips that are bent or distorted. Replace these parts
as well.
ASSEMBLY
Do not allow dirt, grease, or foreign material to
enter the case or transmission components during
assembly. Keep the transmission case and compo-
nents clean. Also make sure the tools and workbench
area used for reassembly operations are equally
clean.
Shop towels used for wiping off tools and your
hands must be made fromlint freematerials. Lint
will stick to transmission parts and could interfere
with valve operation or even restrict fluid passages.
Lubricate transmission clutch and gear compo-
nents with MopartATF +4 during reassembly. Soak
clutch discs in transmission fluid before installation.
Use petroleum jelly on piston seals and o-rings to
ease installation. Petroleum jelly can also be used to
lubricate and hold thrust washers and plates in posi-
tion during assembly.
Do not use chassis grease, bearing grease,
white grease, or similar lubricants on any part.
These types of lubricants can eventually block or
restrict fluid passages and valve operation. Use
petroleum jelly only.
Do not force parts into place. The transmission
components and sub-assemblies are easily installed
by hand when properly aligned. If a part seems dif-
ficult to install, it is either misaligned or incorrectly
Fig. 39 Rear Servo Retaining Snap-Ring
1 - TOOL C-4470
2 - C-CLAMP
3 - REAR SERVO SPRING RETAINER
4 - RETAINER SNAP-RING
21 - 166 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
assembled. Verify that thrust washers, thrust plates
and seal rings are correctly positioned.
The planetary geartrain, front/rear clutch assem-
blies and oil pump are all much easier to install
when the transmission case is upright. Either tilt the
case upward with wood blocks, or cut a hole in the
bench large enough for the intermediate shaft and
rear support. Then lower the shaft and support into
the hole and support the rear of the case directly on
the bench.
FRONT/REAR SERVO
(1) Lubricate rear servo piston seal with ATF +4.
Lubricate servo bore in case with ATF +4.
(2) Install rear servo piston in case. Position piston
at slight angle to bore and insert piston with twisting
motion (Fig. 40).
(3) Install rear servo spring and retainer in case
bore (Fig. 41). Be sure spring is seated on piston.
(4) Compress rear servo piston with C-clamp or
Valve Spring Compressor C-3422-B and install servo
piston snap-ring (Fig. 42).
(5) Lubricate front servo piston components and
servo bore in case with transmission fluid.
(6) Install front servo piston in bore. Carefully
ªrunº small, suitable tool around piston ring to press
it back into groove and ease installation (Fig. 43).
Rotate piston into bore at same time. Rock piston
slightly to ease piston ring past snap-ring groove and
into bore.
Fig. 40 Rear Servo Piston
1 - REAR SERVO PISTON
Fig. 41 Rear Servo Piston Spring And Retainer
1 - PISTON SPRING
2 - REAR SERVO PISTON
3 - SPRING RETAINER
Fig. 42 Rear Servo Snap Ring
1 - TOOL C-4470
2 - C-CLAMP
3 - REAR SERVO SPRING RETAINER
4 - RETAINER SNAP-RING
DRAUTOMATIC TRANSMISSION - 48RE 21 - 167
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)
PLANETARY GEARTRAIN, FRONT/REAR CLUTCH,
AND FRONT BAND
(1) Remove Alignment Shaft 6227-2, if installed
previously.
(2) Install assembled intermediate shaft and plan-
etary geartrain (Fig. 46).Support shaft carefully
during installation. Do not allow shaft bearing/
bushing surfaces to become nicked or
scratched.
(3) Lubricate intermediate shaft thrust plate with
petroleum jelly and install plate on shaft pilot hub
(Fig. 47).
(4) Check input shaft front seal rings, fiber thrust
washer and rear seal ring (Fig. 48). Be sure the ends
of rear seal ring are hooked together and diagonal
cut ends of front seal rings are firmly seated against
each other as shown. Lubricate seal rings with petro-
leum jelly after checking them.
(5) Assemble front and rear clutches (Fig. 49).
Align lugs on front clutch discs. Mount front clutch
on rear clutch. Turn front clutch retainer back and
forth until front clutch discs are fully seated on rear
clutch splined hub.
Fig. 46 Intermediate Shaft And Planetary Geartrain
1 - INTERMEDIATE SHAFT AND PLANETARY GEAR TRAIN
ASSEMBLY
Fig. 47 Intermediate Shaft Thrust Plate
1 - SHAFT THRUST PLATE
2 - INTERMEDIATE SHAFT PILOT HUB
Fig. 48 Input Shaft Seal Ring And Thrust Washer
1 - TORLONTFRONT SEAL RINGS
2 - INPUT SHAFT
3 - REAR SEAL RING
4 - THRUST WASHER
DRAUTOMATIC TRANSMISSION - 48RE 21 - 169
AUTOMATIC TRANSMISSION - 48RE (Continued)
(6) Install intermediate shaft thrust washer in hub
of rear clutch retainer (Fig. 50). Use petroleum jelly
to hold washer in place. Position washer so grooves
are facing outward.Washer only fits one way in
clutch retainer hub.
(7) Place transmission case in upright position, or
place blocks under front end of transmission repair
stand to tilt case rearward. This makes it easier to
install front/rear clutch assembly.
(8) Align discs in rear clutch. Then install and
engage assembly in front planetary and driving shell
(Fig. 51). Turn clutch retainers back and forth until
both clutches are seated.
(9) Position front band lever in case and over servo
rod guide. Then install front band lever pin in case
and slide it through lever.
(10) Coat threads of front band pin access plug
with sealer and install it in case. Tighten plug to 17
N´m (13 ft. lbs.) torque.
Fig. 50 Intermediate Shaft Thrust Washer
1 - BE SURE WASHER GROOVES FACE OUT AS SHOWN
2 - REAR CLUTCH RETAINER HUB
3 - SHAFT THRUST WASHER
Fig. 51 Front/Rear Clutch Assemblies
1 - FRONT AND REAR CLUTCH ASSEMBLIES
Fig. 49 Assembling Front And Rear Clutches
1 - FRONT CLUTCH ASSEMBLY
2 - REAR CLUTCH ASSEMBLY
3 - REAR CLUTCH SPLINED HUB
21 - 170 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
(11) Slide front band over front clutch retainer and
install front band strut and anchor (Fig. 52).
(12) Tighten front band adjusting screw until band
is tight on clutch retainer. This will hold clutches in
place while oil pump is being installed.Verify that
front/rear clutch assembly is still properly
seated before tightening band.
OIL PUMP
(1) Install oil pump Pilot Studs C-3288-B in case
(Fig. 53).(2) Install new oil pump gasket on pilot studs and
seat it in case. Be sure gasket is properly aligned
with fluid passages in case (Fig. 53).
(3) Coat the reaction shaft thrust washer with
petroleum jelly to hold it in place. Then install
washer over reaction shaft hub and seat it on pump
(Fig. 54).
CAUTION: The thrust washer bore (I.D.), is cham-
fered on one side. Make sure the chamfered side is
installed so it faces the pump.
Fig. 53 Oil Pump Gasket And Pilot Studs
1 - OIL PUMP GASKET
2 - PILOT STUDS C-3288-B
Fig. 54 Front Clutch Thrust Washer Installation
1 - THRUST WASHER
2 - CHAMFERED SIDE OF WASHER BORE GOES TOWARD
PUMP
Fig. 55 Reaction Shaft Seal Ring And Thrust Washer
1 - SEAL RINGS
2 - REACTION SHAFT SUPPORT
3 - THRUST WASHER (FIBER)
Fig. 52 Front Band And Linkage
1 - LEVER
2 - STRUT
3 - ANCHOR
4 - FRONT BAND
DRAUTOMATIC TRANSMISSION - 48RE 21 - 171
AUTOMATIC TRANSMISSION - 48RE (Continued)