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(20) Remove kickdown detent, kickdown valve, and
throttle valve and spring (Fig. 306).
DR VALVE BODY (Continued)
AUTOMATIC TRANSMISSION - 46RE
21 - 291
1 - UPPER HOUSING 2 - REGULATOR VALVE 3 - SWITCH VALVE 4 - REGULATOR VALVE SPRING 5 - KICKDOWN VALVE 6 - KICKDOWN DETENT 7 - THROTTLE VALVE AND SPRING
Fig.306UpperHousingControlValveLocations
8 - MANUAL VALVE 9 - 1-2 GOVERNOR PLUG 10 - GOVERNOR PLUG COVER 11 - THROTTLE PLUG 12 - 2-3 GOVERNOR PLUG 13 - SHUTTLE VALVE PRIMARY SPRING
Fig.307AccumulatorHousingScrewLocations
1 - LOOSEN THIS SCREW 2 - REMOVE THESE SCREWS 3 - 3-4 ACCUMULATOR HOUSING
(22) Carefully rotate 3-4 accumulator housing upward and remove 3-4 shift valve spring and con- verter clutch valve plug and spring (Fig. 308).
Fig.3083-4ShiftAndConverterClutchValve
SpringsandPlug
1 - ACCUMULATOR HOUSING 2 - CONVERTER CLUTCH VALVE SPRING 3 - CLUTCH VALVE PLUG 4 - 3-4 SHIFT VALVE SPRING
21 - 292
VALVE BODY (Continued)AUTOMATIC TRANSMISSION - 46RE
DR
(23) Remove left-side screw and remove 3-4 accu-
mulator housing from valve body (Fig. 309).
(24) Bend back tabs on boost valve tube brace (Fig.
310).
(26) Turn valve body over so lower housing is fac- ing upward (Fig. 312). In this position, the two check balls in upper housing will remain in place and not fall out when lower housing and separator plate are removed.
(27) Remove screws attaching valve body lower housing to upper housing and transfer plate (Fig. 312). Note position of boost valve tube brace for assembly reference.
(28) Remove lower housing and overdrive separa-
tor plate from transfer plate (Fig. 312).
Fig.309AccumulatorHousing,ValveSprings,and
Plug
1 - 3-4 SHIFT VALVE SPRING 2 - CONVERTER CLUTCH VALVE SPRING AND PLUG 3 - 3-4 ACCUMULATOR HOUSING
Fig.311BoostValveTube
1 - BOOST VALVE TUBE 2 - LOWER HOUSING 3 - DISENGAGE THIS END OF TUBE FIRST 4 - UPPER HOUSING
Fig.310BoostValveTubeBrace
1 - BOOST VALVE TUBE 2 - TUBE BRACE (DOUBLE TAB)
(25) Remove boost valve connecting tube (Fig. 311). Disengage tube from upper housing port first. Then rock opposite end of tube back and forth to work it out of lower housing.
CAUTION: Do not use tools to loosen or pry the connecting tube out of the valve body housings. Loosen and remove the tube by hand only.
Fig.312LowerHousing
1 - LOWER HOUSING 2 - OVERDRIVE SEPARATOR PLATE 3 - TRANSFER PLATE AND UPPER HOUSING
DR VALVE BODY (Continued)
AUTOMATIC TRANSMISSION - 46RE
21 - 293
(29) Remove the Number 10 check ball from the transfer plate (Fig. 313). The check ball is approxi- mately 4.8 mm (3/16 in.) in diameter.
(30) Remove transfer plate from upper housing
(Fig. 314).
(31) Turn transfer plate over so upper housing sep-
arator plate is facing upward.
(32) Remove upper housing separator plate from transfer plate (Fig. 315). Note position of filter in separator plate for assembly reference.
(33) Remove rear clutch and rear servo check balls location for
from transfer plate. Note check ball assembly reference (Fig. 316).
Fig.315UpperHousingSeparatorPlate
1 - TRANSFER PLATE 2 - UPPER HOUSING SEPARATOR PLATE 3 - FILTER SCREEN 4 - BRACE
Fig.313Number10CheckBall
1 - NUMBER 10 CHECK BALL (3/169)
Fig.316RearClutchandRearServoCheckBall
Locations
1 - REAR CLUTCH CHECK BALL 2 - REAR SERVO CHECK BALL 3 - TRANSFER PLATE
Fig.314TransferPlate
1 - UPPER HOUSING 2 - TRANSFER PLATE
AUTOMATIC TRANSMISSION - 46RE
21 - 294
VALVE BODY (Continued) VALVE BODY UPPER HOUSINGDR
(1) Note location of check balls in valve body upper housing (Fig. 317). Then remove the one large diam- eter and the six smaller diameter check balls.
(2) Remove governor plug and shuttle valve covers
(Fig. 319).
(3) Remove E-clip that secures shuttle valve sec-
ondary spring on valve stem (Fig. 318).
(4) Remove throttle plug, primary spring, shuttle valve, secondary spring, and spring guides (Fig. 319). (5) Remove boost valve retainer, spring and valve
if not previously removed.
(6) Remove throttle plug and 1-2 and 2-3 governor
plugs (Fig. 306).
(7) Turn upper housing around and remove limit
valve and shift valve covers (Fig. 320).
(8) Remove limit valve housing. Then remove retainer, spring, limit valve, and 2-3 throttle plug from limit valve housing (Fig. 320).
(9) Remove 1-2 shift control valve and spring (Fig.
320).
Fig.318ShuttleValveE-ClipAndSecondarySpring 1 - E-CLIP 2 - SECONDARY SPRING AND GUIDES 3 - SHUTTLE VALVE
(10) Remove 1-2 shift valve and spring (Fig. 320). (11) Remove 2-3 shift valve and spring from valve
body (Fig. 320).
(12) Remove pressure plug cover (Fig. 320). (13) Remove line pressure plug, sleeve, throttle
pressure plug and spring (Fig. 320).
VALVE BODY LOWER HOUSING (1) Remove timing valve cover. (2) Remove 3-4 timing valve and spring. (3) Remove 3-4 quick fill valve, spring and plug. (4) Remove 3-4 shift valve and spring. (5) Remove converter clutch valve, spring and plug
(Fig. 321).
and valve spring.
(6) Remove converter clutch timing valve, retainer
3-4 ACCUMULATOR HOUSING
(1) Remove end plate from housing. (2) Remove piston spring. (3) Remove piston. Remove and discard piston
seals (Fig. 322).
Fig.317CheckBallLocationsInUpperHousing
1 - SMALL DIAMETER CHECK BALLS (6) 2 - LARGE DIAMETER CHECK BALL (1)
DR VALVE BODY (Continued)
AUTOMATIC TRANSMISSION - 46RE
21 - 295
Fig.319ShuttleandBoostValveLocation
1 - SPRING 2 - RETAINER 3 - BOOST VALVE 4 - BOOST VALVE PLUG 5 - SPRING GUIDES 6 - E-CLIP 7 - SHUTTLE VALVE SECONDARY SPRING
8 - SHUTTLE VALVE COVER 9 - SHUTTLE VALVE 10 - SHUTTLE VALVE PRIMARY SPRING 11 - GOVERNOR PLUG COVER 12 - THROTTLE PLUG 13 - UPPER HOUSING 14 - BOOST VALVE COVER
21 - 296
VALVE BODY (Continued)AUTOMATIC TRANSMISSION - 46RE
DR
Fig.320UpperHousingShiftValveandPressurePlugLocations
1 - UPPER HOUSING 2 - 1-2 SHIFT VALVE AND SPRING 3 - 2-3 SHIFT VALVE AND SPRING 4 - 2-3 THROTTLE PLUG 5 - LIMIT VALVE HOUSING 6 - LIMIT VALVE COVER 7 - LIMIT VALVE AND SPRING
8 - RETAINER 9 - 1-2 SHIFT CONTROL VALVE AND SPRING 10 - PRESSURE PLUG COVER 11 - LINE PRESSURE PLUG 12 - PLUG SLEEVE 13 - THROTTLE PRESSURE SPRING AND PLUG
DR VALVE BODY (Continued)
AUTOMATIC TRANSMISSION - 46RE
21 - 297
Fig.321LowerHousingShiftValvesandSprings
1 - 3-4 ACCUMULATOR HOUSING 2 - 3-4 SHIFT VALVE AND SPRING 3 - PLUG 4 - SPRING RETAINER 5 - CONVERTER CLUTCH VALVE AND SPRING 6 - CONVERTER CLUTCH TIMING VALVE AND SPRING 7 - OVERDRIVE SEPARATOR PLATE 8 - CASE CONNECTOR 9 - CONVERTER CLUTCH SOLENOID 10 - OVERDRIVE SOLENOID
11 - TIMING VALVE COVER 12 - PLUG 13 - 3-4 TIMING VALVE AND SPRING 14 - LOWER HOUSING 15 - ACCUMULATOR END PLATE 16 - 3-4 ACCUMULATOR PISTON AND SPRING 17 - E-CLIP 18 - 3-4 QUICK FILL SPRING AND VALVE 19 - SOLENOID GASKET 20 - HARNESS
21 - 298
VALVE BODY (Continued)AUTOMATIC TRANSMISSION - 46RE
DR
filter on the solenoid valve is NOT serviceable. Do not try to remove the filter as this will damage the valve housing.
INSPECTION
Inspect the throttle and manual valve levers and shafts. Do not attempt to straighten a bent shaft or correct a loose lever. Replace these components if worn, bent, loose or damaged in any way.
Inspect all of the valve body mating surfaces for scratches, nicks, burrs, or distortion. Use a straight- edge to check surface flatness. Minor scratches may be removed with crocus cloth using only very light pressure.
Minor distortion of a valve body mating surface may be corrected by smoothing the surface with a sheet of crocus cloth. Position the crocus cloth on a surface plate, sheet of plate glass or equally flat sur- face. If distortion is severe or any surfaces are heavily scored, the valve body will have to be replaced.
CAUTION: Many of the valves and plugs, such as the throttle valve, shuttle valve plug, 1-2 shift valve and 1-2 governor plug, are made of coated alumi- num. Aluminum components are identified by the dark color of the special coating applied to the sur- face (or by testing with a magnet). Do not sand alu- minum valves or plugs under any circumstances. This practice could damage the special coating causing the valves/plugs to stick and bind.
Inspect the valves and plugs for scratches, burrs, nicks, or scores. Minor surface scratches on steel valves and plugs can be removed with crocus cloth but do not round off the edges of the valve or plug lands.Maintaining sharpness of these edges is vitally important. The edges prevent foreign matter from lodging between the valves and plugs and the bore.
Inspect all the valve and plug bores in the valve body. Use a penlight to view the bore interiors. Replace the valve body if any bores are distorted or scored. Inspect all of the valve body springs. The springs must be free of distortion, warpage or broken coils.
Check the two separator plates for distortion or damage of any kind. Inspect the upper housing, lower housing, 3-4 accumulator housing, and transfer plate carefully. Be sure all fluid passages are clean and clear. Check condition of the upper housing and transfer plate check balls as well. The check balls and ball seats must not be worn or damaged.
Trial fit each valve and plug in its bore to check freedom of operation. When clean and dry, the valves and plugs should drop freely into the bores.
Fig.3223-4AccumulatorandHousing
1 - ACCUMULATOR PISTON 2 - 3-4 ACCUMULATOR HOUSING 3 - TEFLON SEALS 4 - PISTON SPRING 5 - COVER PLATE AND SCREWS
CLEANING
Clean the valve housings, valves, plugs, springs, and separator plates with a standard parts cleaning solution only. Do not use gasoline, kerosene, or any type of caustic solution.
Do not immerse any of the electrical components in cleaning solution. Clean the governor solenoid and sensor and the dual solenoid and harness assembly by wiping them off with dry shop towels only.
Dry all except the electrical parts with compressed air. Make sure all passages are clean and free from obstructions. Do not use rags or shop towels to dry or wipe off valve body components. Lint from these materials can stick to valve body parts, interfere with valve operation, and clog filters and fluid passages.
Wipe the governor pressure sensor and solenoid valve with dry, lint free shop towels only. The O-rings on the sensor and solenoid valve are the only service- able components. Be sure the vent ports in the sole- noid valve are open and not blocked by dirt or debris. Replace the valve and/or sensor only when DRB scan tool diagnosis indicates this is necessary. Or, if either part has (dented, deformed, broken, etc.).
sustained
physical
damage
CAUTION: Do not turn the small screw at the end of the solenoid valve for any reason. Turning the screw in either direction will ruin solenoid calibra- tion and result in solenoid failure. In addition, the
DR VALVE BODY (Continued)
Valve body bores do not change dimensionally with use. If the valve body functioned correctly when new, it will continue to operate properly after cleaning and inspection. It should not be necessary to replace a valve body assembly unless it is damaged in han- dling.
The only serviceable valve body components are listed below. The remaining valve body components are serviced only as part of a complete valve body assembly. Serviceable parts are: † dual solenoid and harness assembly † solenoid gasket † solenoid case connector O-rings and shoulder bolt† switch valve and spring † pressure adjusting screw and bracket assembly † throttle lever † manual lever and shaft seal † throttle lever shaft seal, washer, and E-clip † fluid filter and screws † detent ball and spring † valve body screws † governor pressure solenoid † governor pressure sensor and retaining clip † park lock rod and E-clip
ASSEMBLY
CAUTION: Do not force valves or plugs into place during reassembly. If the valve body bores, valves and plugs are free of distortion or burrs, the valve body components should all slide into place easily. In addition, do not overtighten the transfer plate and valve body screws during reassembly. Over- tightening can distort the housings resulting in valve sticking, cross leakage and unsatisfactory operation. Tighten valve body screws to recom- mended torque only.
LOWER HOUSING
(1) Lubricate valves, springs, and the housing valve and plug bores with clean transmission fluid (Fig. 321).
(2) Install 3-4 timing valve spring and valve in
lower housing.
housing.
(3) Install 3-4 quick fill valve in lower housing. (4) Install 3-4 quick fill valve spring and plug in
(5) Install timing valve end plate. Tighten end
plate screws to 4 N·m (35 in. lbs.) torque.
AUTOMATIC TRANSMISSION - 46RE
21 - 299
3-4 ACCUMULATOR
(1) Lubricate accumulator piston, seals and hous- ing piston bore with clean transmission fluid (Fig. 322).
(2) Install new seal rings on accumulator piston. (3) Install piston and spring in housing. (4) Install end plate on housing.
TRANSFER PLATE
(1) Install rear clutch and rear servo check balls in
transfer plate (Fig. 323).
(2) Install filter screen in upper housing separator
plate (Fig. 324).
Fig.323RearClutchAndRearServoCheckBall
Locations
1 - REAR CLUTCH CHECK BALL 2 - REAR SERVO CHECK BALL 3 - TRANSFER PLATE
Fig.324SeparatorPlateFilterScreenInstallation 1 - UPPER HOUSING SEPARATOR PLATE 2 - FILTER SCREEN
21 - 300
VALVE BODY (Continued)AUTOMATIC TRANSMISSION - 46RE
DR
(3) Align and position upper housing separator
plate on transfer plate (Fig. 325).
(4) Install brace plate (Fig. 325). Tighten brace
attaching screws to 4 N·m (35 in. lbs.) torque.
(5) Install remaining separator plate attaching screws. Tighten screws to 4 N·m (35 in. lbs.) torque.
is approximately 4.8 mm (3/16 in.)
in check ball diameter. The remaining 6 check balls are approxi- mately 6.3 mm (1/4 in.) in diameter.
(2) Position assembled transfer plate and upper housing separator plate on upper housing (Fig. 327). Be sure filter screen is seated in proper housing recess.
(3) Install the Number 10 check ball
into the transfer plate (Fig. 328). The check ball is approxi- mately 4.8 mm (3/16 in.) in diameter.
Fig.325BracePlate
1 - BRACE 2 - TRANSFER PLATE 3 - SEPARATOR PLATE
UPPER AND LOWER HOUSING
(1) Position upper housing so internal passages and check ball seats are facing upward. Then install check balls in housing (Fig. 326). Eight check balls are used. The single large check ball is approxi- mately 8.7 mm (11/32 in.) diameter. The single small
Fig.327InstallingTransferPlateOnUpperHousing 1 - FILTER SCREEN 2 - TRANSFER PLATE/SEPARATOR PLATE ASSEMBLY 3 - UPPER HOUSING
Fig.326CheckBallLocationsInUpperHousing
1 - SMALL DIAMETER CHECK BALLS (6) 2 - LARGE DIAMETER CHECK BALL (1)
Fig.328Number10CheckBall
1 - NUMBER 10 CHECK BALL (3/169)
AUTOMATIC TRANSMISSION - 46RE
21 - 301
UPPER HOUSING VALVE AND PLUG
Refer to (Fig. 331), (Fig. 332) and (Fig. 333) to per-
form the following steps.
(1) Lubricate valves, plugs, springs with clean
transmission fluid.
(2) Assemble regulator valve line pressure plug, sleeve, throttle plug and spring. Insert assembly in upper housing and install cover plate. Tighten cover plate screws to 4 N·m (35 in. lbs.) torque.
(3) Install 1-2 and 2-3 shift valves and springs. (4) Install 1-2 shift control valve and spring. (5) Install retainer, spring,
limit valve, and 2-3
throttle plug from limit valve housing.
(6) Install
limit valve housing and cover plate.
Tighten screws to 4 N·m (35 in. lbs.). (7) Install shuttle valve as follows:
(a) Insert plastic guides in shuttle valve second-
ary spring and install spring on end of valve.
(b) Install shuttle valve into housing. (c) Hold shuttle valve in place. (d) Compress secondary spring and install E-clip
in groove at end of shuttle valve.
(e) Verify that spring and E-clip are properly
seated before proceeding. (8) Install shuttle valve cover plate. Tighten cover
plate screws to 4 N·m (35 in. lbs.) torque.
(9) Install 1-2 and 2-3 valve governor plugs in
shuttle valve primary spring and
valve body.
(10) Install throttle plug.
(11) Align and install governor plug cover. Tighten
cover screws to 4 N·m (35 in. lbs.) torque.
DR VALVE BODY (Continued)
(4) Position lower housing separator plate on
transfer plate (Fig. 329).
(5) Install
lower housing on assembled transfer
plate and upper housing (Fig. 330).
(6) Install and start all valve body screws by hand except for the screws to hold the boost valve tube brace. Save those screws for later installation. Then tighten screws evenly to 4 N·m (35 in. lbs.) torque. Start at center and work out to sides when tighten- ing screws (Fig. 330).
Fig.329LowerHousingSeparatorPlate
1 - BE SURE TO ALIGN BORES 2 - TRANSFER PLATE 3 - LOWER HOUSING (OVERDRIVE) SEPARATOR PLATE
Fig.330InstallingLowerHousingOnTransferPlate
AndUpperHousing
1 - VALVE BODY SCREWS (13) 2 - LOWER HOUSING 3 - UPPER HOUSING 4 - TRANSFER PLATE
21 - 302
VALVE BODY (Continued)AUTOMATIC TRANSMISSION - 46RE
DR
Fig.331ShuttleandBoostValveLocations
1 - SPRING 2 - RETAINER 3 - BOOST VALVE 4 - BOOST VALVE PLUG 5 - SPRING GUIDES 6 - E-CLIP 7 - SHUTTLE VALVE SECONDARY SPRING
8 - SHUTTLE VALVE COVER 9 - SHUTTLE VALVE 10 - SHUTTLE VALVE PRIMARY SPRING 11 - GOVERNOR PLUG COVER 12 - THROTTLE PLUG 13 - UPPER HOUSING 14 - BOOST VALVE COVER
DR VALVE BODY (Continued)
AUTOMATIC TRANSMISSION - 46RE
21 - 303
1 - UPPER HOUSING 2 - REGULATOR VALVE 3 - SWITCH VALVE 4 - REGULATOR VALVE SPRING 5 - KICKDOWN VALVE 6 - KICKDOWN DETENT 7 - THROTTLE VALVE AND SPRING
Fig.332UpperHousingControlValveLocations
8 - MANUAL VALVE 9 - 1-2 GOVERNOR PLUG 10 - GOVERNOR PLUG COVER 11 - THROTTLE PLUG 12 - 2-3 GOVERNOR PLUG 13 - SHUTTLE VALVE PRIMARY SPRING
21 - 304
VALVE BODY (Continued)AUTOMATIC TRANSMISSION - 46RE
DR
Fig.333UpperHousingShiftValveandPressurePlugLocations
1 - UPPER HOUSING 2 - 1-2 SHIFT VALVE AND SPRING 3 - 2-3 SHIFT VALVE AND SPRING 4 - 2-3 THROTTLE PLUG 5 - LIMIT VALVE HOUSING 6 - LIMIT VALVE COVER 7 - LIMIT VALVE AND SPRING
BOOST VALVE TUBE AND BRACE
8 - RETAINER 9 - 1-2 SHIFT CONTROL VALVE AND SPRING 10 - PRESSURE PLUG COVER 11 - LINE PRESSURE PLUG 12 - PLUG SLEEVE 13 - THROTTLE PRESSURE SPRING AND PLUG
(1) Position valve body assembly so lower housing
is facing upward (Fig. 334).
(2) Lubricate tube ends and housing ports with
transmission fluid or petroleum jelly.
(3) Start tube in lower housing port first. Then swing tube downward and work opposite end of tube into upper housing port (Fig. 334).
(4) Insert and seat each end of tube in housings. (5) Slide tube brace under tube and into alignment
with valve body screw holes (Fig. 335).
(6) Install and finger tighten three screws that secure tube brace to valve body housings (Fig. 335). (7) Bend tube brace tabs up and against tube to
hold it in position (Fig. 336).
(8) Tighten all valve body housing screws to 4 N·m (35 in. lbs.) torque after tube and brace are installed. Tighten screws in diagonal pattern starting at center and working outward.
Fig.334BoostValveTube
1 - BOOST VALVE TUBE 2 - LOWER HOUSING 3 - DISENGAGE THIS END OF TUBE FIRST 4 - UPPER HOUSING
DR VALVE BODY (Continued)
AUTOMATIC TRANSMISSION - 46RE
21 - 305
(5) Position plug on end of converter clutch valve spring. Then compress and hold springs and plug in place with fingers of one hand.
(6) Swing accumulator housing upward over valve
springs and plug.
(7) Hold accumulator housing firmly in place and install remaining two attaching screws. Be sure springs and clutch valve plug are properly seated (Fig. 338). Tighten screws to 4 N·m (35 in. lbs.).
Fig.335BoostValveTubeAndBrace
1 - BOOST VALVE TUBE 2 - TUBE BRACE
Fig.336SecuringBoostValveTubeWithBrace
Tabs
1 - BEND TABS UP AGAINST TUBE AS SHOWN
3-4 ACCUMULATOR
(1) Position converter clutch valve and 3-4 shift
valve springs in housing (Fig. 337).
(2) Loosely attach accumulator housing with right- side screw (Fig. 337). Install only one screw at this time as accumulator must be free to pivot upward for ease of installation.
(3) Install 3-4 shift valve and spring. (4) Install
converter
clutch timing valve and
spring.
Fig.337ConverterClutchAnd3-4ShiftValve
Springs
1 - RIGHT-SIDE SCREW 2 - 3-4 ACCUMULATOR 3 - 3-4 SHIFT VALVE SPRING 4 - CONVERTER CLUTCH VALVE SPRING
Fig.338Seating3-4AccumulatorOnLower
Housing
1 - ACCUMULATOR BOX 2 - CONVERTER CLUTCH VALVE PLUG
AUTOMATIC TRANSMISSION - 46RE
21 - 306
VALVE BODY (Continued) VALVE BODY FINALDR
(1) Install boost valve, valve spring, retainer and cover plate. Tighten cover plate screws to 4 N·m (35
in. lbs.) torque.(2) Insert manual
lever detent spring in upper
housing.
(3) Position detent ball on end of spring. Then hold detent ball and spring in detent housing with Retainer Tool 6583 (Fig. 339).
(4) Install throttle lever in upper housing. Then lever over throttle lever and start
install manual manual lever into housing.
(5) Align manual lever with detent ball and man- ual valve. Hold throttle lever upward. Then press down on manual lever until fully seated. Remove detent ball retainer tool after lever is seated.
(6) Then install manual
lever seal, washer and
E-clip.
valve.
(7) Verify that throttle lever is aligned with end of kickdown valve stem and that manual lever arm is engaged in manual valve (Fig. 340).
(8) Position line pressure adjusting screw in
adjusting screw bracket.
(9) Install spring on end of line pressure regulator
(10) Install switch valve spring on tang at end of
adjusting screw bracket.
(11) Install manual valve. (12) Install throttle valve and spring. (13) Install kickdown valve and detent. (14) Install pressure regulator valve. (15) Install switch valve. (16) Position adjusting screw bracket on valve body. Align valve springs and press bracket into place. Install short, upper bracket screws first and long bottom screw last. Verify that valve springs and bracket are properly aligned. Then tighten all three bracket screws to 4 N·m (35 in. lbs.) torque.
Fig.340ManualAndThrottleLeverAlignment
1 - THROTTLE LEVER 2 - MANUAL LEVER VALVE ARM 3 - MANUAL VALVE 4 - KICKDOWN VALVE
(17) Perform Line Pressure and Throttle Pressure adjustments. (Refer to 21 - TRANSMISSION/TRANS- AXLE/AUTOMATIC/VALVE - ADJUST- MENTS)
BODY
(18) Lubricate solenoid case connector O-rings and shaft of manual lever with light coat of petroleum jelly.
(19) Attach solenoid case connector to 3-4 accumu- lator with shoulder-type screw. Connector has small locating tang that fits in dimple at top of accumula- tor housing (Fig. 341). Seat tang in dimple before tightening connector screw.
Fig.339DetentBallSpring
1 - SPECIAL TOOL 6583 POSITIONED ON DETENT HOUSING
1 - SOLENOID HARNESS CASE CONNECTOR 2 - 3-4 ACCUMULATOR HOUSING
Fig.341SolenoidHarnessCaseConnector
ShoulderBolt
DR VALVE BODY (Continued)
(20) Install solenoid assembly and gasket. Tighten lbs.)
solenoid attaching screws to 8 N·m (72 in. torque.
(21) Verify that solenoid wire harness is properly routed (Fig. 342). Solenoid harness must be clear of manual lever and park rod and not be pinched between accumulator housing and cover.
Fig.342SolenoidHarnessRouting
1 - OVERDRIVE/CONVERTER SOLENOID WIRE HARNESS 2 - 3-4 ACCUMULATOR COVER PLATE
GOVERNOR BODY, SENSOR AND SOLENOID
(1) Turn valve body assembly over so accumulator
side of transfer plate is facing down.
(2) Install new O-rings on governor pressure sole-
noid and sensor.
(3) Lubricate solenoid and sensor O-rings with
clean transmission fluid.
(4) Install governor pressure sensor in governor
(5) Install governor pressure solenoid in governor body. Push solenoid in until it snaps into place in body.
(6) Position governor body gasket on transfer
body.
plate.
(7) Install retainer plate on governor body and around solenoid. Be sure solenoid connector is posi- tioned in retainer cutout.
(8) Align screw holes in governor body and trans- fer plate. Then install and tighten governor body screws to 4 N·m (35 in. lbs.) torque.
(9) Connect harness wires to governor pressure
solenoid and governor pressure sensor.
(10) Install fluid filter and pan.
AUTOMATIC TRANSMISSION - 46RE
21 - 307
(11) Lower vehicle. (12) Fill transmission with recommended fluid and
road test vehicle to verify repair.
INSTALLATION
(1) Check condition of O-ring seals on valve body harness connector (Fig. 343). Replace seals on con- nector body if cut or worn.
(2) Check condition of manual lever shaft seal in transmission case. Replace seal if lip is cut or worn. Install new seal with 15/16 deep well socket (Fig. 344).
(3) Check condition of seals on accumulator piston.
Install new piston seals, if necessary.
(4) Verify that transmission range sensor is NOT installed. Valve body cannot be installed with sensor in place.
(5) Place valve body manual lever in low (1 posi- tion) so ball on park lock rod will be easier to install in sprag.
(6) Lubricate shaft of manual lever with petroleum jelly. This will ease inserting shaft through seal in case.
(7) Lubricate seal rings on valve body harness con-
nector with petroleum jelly.
(8) Position valve body in case and work end of park lock rod into and through pawl sprag. Turn pro- peller shaft to align sprag and park lock teeth if nec- essary. The rod will click as it enters pawl. Move rod to check engagement.
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 this cavity.
(9) Install accumulator spring and piston into case. Then swing valve body over piston and outer spring to hold it in place.
(10) Align accumulator piston and outer spring, manual lever shaft and electrical connector in case. (11) Then seat valve body in case and install one
or two bolts to hold valve body in place.
(12) Tighten valve body bolts alternately and
evenly to 11 N·m (100 in. lbs.) torque.
(13) Install new fluid filter on valve body. Tighten
filter screws to 4 N·m (35 in. lbs.) torque.
(14) Install throttle and gearshift levers on valve
body manual lever shaft.
21 - 308
VALVE BODY (Continued)AUTOMATIC TRANSMISSION - 46RE
DR
(15) Check and adjust front and rear bands if nec-
essary.
(16) Connect solenoid case connector wires. (17) Install the transmission range sensor. (18) Install oil pan and new gasket. Tighten pan
bolts to 17 N·m (13 ft. lbs.) torque.
(19) Lower vehicle and fill
transmission with
Mopart ATF +4, Automatic Transmission fluid.
(20) Check and adjust gearshift and throttle valve
cables, if necessary.
Fig.343ValveBodyHarnessConnectorO-RingSeal 1 - CONNECTOR O-RINGS 2 - VALVE BODY HARNESS CONNECTOR 3 - HARNESS
ADJUSTMENTS - VALVE BODY
CONTROL PRESSURE ADJUSTMENTS
valve body;
There are two control pressure adjustments on the † Line Pressure † Throttle Pressure Line and throttle pressures are interdependent because each affects shift quality and timing. As a result, both adjustments must be performed properly and in the correct sequence. Adjust line pressure first and throttle pressure last.
LINE PRESSURE ADJUSTMENT
Measure distance from the valve body to the inner edge of the adjusting screw with an accurate steel scale (Fig. 345).
Distance should be 33.4 mm (1-5/16 in.). If adjustment is required, turn the adjusting screw
in, or out, to obtain required distance setting.
NOTE: The 33.4 mm (1-5/16 in.) setting is an approximate setting. Manufacturing tolerances may make it necessary to vary from this dimension to obtain desired pressure.
One complete turn of the adjusting screw changes
line pressure approximately 1-2/3 psi (9 kPa).
Turning the adjusting screw counterclockwise increases pressure while turning the screw clockwise decreases pressure.
Fig.344ManualLeverShaftSeal
1 - 15/1688 SOCKET 2 - SEAL
Fig.345LinePressureAdjustment
1 - WRENCH 2 - 1–5/16 INCH
DR VALVE BODY (Continued)
THROTTLE PRESSURE ADJUSTMENT
AUTOMATIC TRANSMISSION - 46RE
21 - 309
Insert Gauge Tool C-3763 between the throttle
lever cam and the kickdown valve stem (Fig. 346).
Push the gauge tool inward to compress the kick- down valve against the spring and bottom the throt- tle valve.
Maintain pressure against kickdown valve spring. Turn throttle lever stop screw until the screw head touches throttle lever tang and the throttle lever cam touches gauge tool.
NOTE: The kickdown valve spring must be fully compressed and the kickdown valve completely bottomed to obtain correct adjustment.
Fig.346ThrottlePressureAdjustment
1 - HEX WRENCH (IN THROTTLE LEVER ADJUSTING SCREW) 2 - SPECIAL TOOL C-3763 (POSITIONED BETWEEN THROTTLE LEVER AND KICKDOWN VALVE)
21 - 310
AUTOMATIC TRANSMISSION - 48RE
AUTOMATIC TRANSMISSION - 48RE
TABLE OF CONTENTS
page
DR
page
AUTOMATIC TRANSMISSION - 48RE
ELECTRONIC GOVERNOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 312
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 314
DIAGNOSIS AND TESTINGDIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION . . . . . . . . . . . . . . . . . . . . . 320
DIAGNOSIS AND TESTING - PRELIMINARY . . 320
DIAGNOSIS AND TESTING - ROADTESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
DIAGNOSIS AND TESTING - HYDRAULIC
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 376
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 377
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 379EXTENSION HOUSING SEAL
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 380FLUID AND FILTER
DIAGNOSIS AND TESTING
PRESSURE TEST . . . . . . . . . . . . . . . . . . . . 321
DIAGNOSIS AND TESTING - EFFECTS OF
DIAGNOSIS AND TESTING - AIR TESTING
TRANSMISSION CLUTCH AND BAND OPERATION . . . . . . . . . . . . . . . . . . . . . . . . 324
DIAGNOSIS AND TESTING - CONVERTER
INCORRECT FLUID LEVEL . . . . . . . . . . . . . 381
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID . . . . . . . . . . . . . . . . . . . . . . . 381
DIAGNOSIS AND TESTING - FLUID
HOUSING FLUID LEAK . . . . . . . . . . . . . . . . 324
CONTAMINATION . . . . . . . . . . . . . . . . . . . . 381
DIAGNOSIS AND TESTING - DIAGNOSIS
STANDARD PROCEDURE
CHARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
STANDARD PROCEDURE - FLUID LEVEL
. . . . . . . . . . . . . . . . . . . . . 368
FRONT SERVO
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR . . . . . . . . . . . . . . . . . . . . . 337
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 339
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 345
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 345
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 353
SCHEMATICS AND DIAGRAMSHYDRAULIC SCHEMATICS . . . . . . . . . . . . . 355
SPECIFICATIONS TRANSMISSION
SPECIAL TOOLS
RE TRANSMISSION
. . . . . . . . . . . . . . . . . . 370
ACCUMULATOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 372
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 373
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 373BANDS
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 373
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 374
ADJUSTMENTSADJUSTMENT - BANDS
. . . . . . . . . . . . . . . 374
BRAKE TRANSMISSION SHIFT INTERLOCK
SYSTEM DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 375
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 375
DIAGNOSIS AND TESTING - BRAKETRANSMISSION SHIFT INTERLOCK . . . . . . 375
ADJUSTMENTS - BRAKE TRANSMISSION
SHIFT INTERLOCK
. . . . . . . . . . . . . . . . . . . 376
CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
STANDARD PROCEDURE - FLUID AND
FILTER REPLACEMENT . . . . . . . . . . . . . . . 383
STANDARD PROCEDURE - TRANSMISSION
FILL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
FRONT CLUTCH
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 384
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 384
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 384
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 385
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 386DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 387
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 387
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 388
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 388
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 388GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 390
ADJUSTMENTSGEARSHIFT CABLE
. . . . . . . . . . . . . . . . . . 391
OIL PUMP
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 392
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 392
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 393
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 393
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 393DR
AUTOMATIC TRANSMISSION - 48RE
21 - 311
OUTPUT SHAFT FRONT BEARING
REAR SERVO
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 395OUTPUT SHAFT REAR BEARING
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 396DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 429
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 429
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 430
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 430OVERDRIVE CLUTCH
SHIFT MECHANISM
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 396
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 396DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 430
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 430OVERDRIVE SWITCH
SOLENOID
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 397
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 397
DIAGNOSIS AND TESTING - OVERDRIVEELECTRICAL CONTROLS
. . . . . . . . . . . . . . 397
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 397OVERDRIVE UNIT
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 399
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 406
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 406
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 414DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 431
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 431SPEED SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 431
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 431THROTTLE VALVE CABLE
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 432
ADJUSTMENTS - THROTTLE VALVE CABLE . 432TORQUE CONVERTER
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 434
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 438
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 439OVERRUNNING CLUTCH CAM/OVERDRIVE
TORQUE CONVERTER DRAINBACK VALVE
PISTON RETAINER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 415
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 415
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 415
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 416
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 416PISTONS
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 418
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 418PLANETARY GEARTRAIN/OUTPUT SHAFT
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 420
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 420
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 421
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 422
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 423REAR CLUTCH
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 426
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 427
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 427
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 428
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 428DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 440
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 440
STANDARD PROCEDURE - TORQUECONVERTER DRAINBACK VALVE . . . . . . . . 440
TRANSMISSION RANGE SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 441
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 441
DIAGNOSIS AND TESTING - TRANSMISSIONRANGE SENSOR (TRS)
. . . . . . . . . . . . . . . . 442
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 444TRANSMISSION TEMPERATURE SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 445
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 445VALVE BODY
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 445
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 450
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . 465
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . 476
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 486
ADJUSTMENTS - VALVE BODY . . . . . . . . . . . 48721 - 312
AUTOMATIC TRANSMISSION - 48RE
DR
AUTOMATIC TRANSMISSION - 48RE DESCRIPTION
The 48RE (Fig. 1) is a four speed fully automatic transmission with an electronic governor. The 48RE is equipped with a lock-up clutch in the torque con- verter. First through third gear ranges are provided by the clutches, bands, overrunning clutch, and plan- etary gear sets in the transmission. Fourth gear range is provided by the overdrive unit that contains an overdrive clutch, direct clutch, planetary gear set, and overrunning clutch.
The transmission contains a front, rear, and direct clutch which function as the input driving compo- nents. It also contains the kickdown (front) and the
low/reverse (rear) bands which, along with the over- running clutch and overdrive clutch, serve as the holding components. The driving and holding compo- nents combine to select the necessary planetary gear components, in the front, rear, or overdrive planetary gear set, transfer the engine power from the input shaft through to the output shaft.
The valve body is mounted to the lower side of the transmission and contains the valves to control pres- sure regulation, fluid flow control, and clutch/band application. The oil pump is mounted at the front of the transmission and is driven by the torque con- verter hub. The pump supplies the oil pressure nec- essary for clutch/band actuation and transmission lubrication.
DR AUTOMATIC TRANSMISSION - 48RE (Continued)
AUTOMATIC TRANSMISSION - 48RE
21 - 313
21 - 314
AUTOMATIC TRANSMISSION - 48RE (Continued)AUTOMATIC TRANSMISSION - 48RE
DR
1 - TORQUE CONVERTER 2 - INPUT SHAFT 3 - OIL PUMP 4 - FRONT BAND 5 - FRONT CLUTCH 6 - REAR CLUTCH 7 - PLANETARIES 8 - REAR BAND 9 - OVERRUNNING CLUTCH
10 - OVERDRIVE CLUTCH 11 - DIRECT CLUTCH 12 - PLANETARY GEAR 13 - INTERMEDIATE SHAFT 14 - OVERDRIVE OVERRUNNING CLUTCH 15 - DIRECT CLUTCH SPRING 16 - OVERDRIVE PISTON RETAINER 17 - OIL PAN 18 - VALVE BODY
IDENTIFICATION
Transmission identification numbers are stamped on the left side of the case just above the oil pan gas- ket surface (Fig. 2). Refer to this information when ordering replacement parts.
Fig.2TransmissionPartAndSerialNumber
Location
1 - PART NUMBER 2 - BUILD DATE 3 - SERIAL NUMBER
GEAR RATIOS
The 48RE gear ratios are:
1st . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.45:1
2nd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.45:1
3rd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.00:1
4th . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.69:1
Rev. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.20:1OPERATION
The application of each driving or holding compo- nent is controlled by the valve body based upon the manual lever position, throttle pressure, and gover- nor pressure. The governor pressure is a variable pressure input to the valve body and is one of the signals that a shift is necessary. First through fourth gear are obtained by selectively applying and releas- ing the different clutches and bands. Engine power is thereby routed to the various planetary gear assem- blies which combine with the overrunning clutch assemblies to generate the different gear ratios. The torque converter clutch is hydraulically applied and is released when fluid is vented from the hydraulic circuit by the torque converter control (TCC) solenoid on the valve body. The torque converter clutch is con- trolled by the Powertrain Control Module (PCM). The torque converter clutch engages in fourth gear, and in third gear under various conditions, such as when the O/D switch is OFF, when the vehicle is cruising on a level surface after the vehicle has warmed up. The torque converter clutch can also be engaged in the manual second gear position if high transmission temperatures are sensed by the PCM. The torque converter clutch will disengage momentarily when an increase in engine load is sensed by the PCM, such as when the vehicle begins to go uphill or the throttle pressure is increased. The torque converter clutch feature increases fuel economy and reduces the transmission fluid temperature.
Since the overdrive clutch is applied in fourth gear only and the direct clutch is applied in all ranges except fourth gear, the transmission operation for park, neutral, and first through third gear will be described first. Once these powerflows are described, the third to fourth shift sequence will be described.
DR AUTOMATIC TRANSMISSION - 48RE (Continued) PARK POWERFLOW
NEUTRAL POWERFLOW
AUTOMATIC TRANSMISSION - 48RE
21 - 315
With the gear selector in the NEUTRAL position (Fig. 4), the power flow of the transmission is essen- tially the same as in the park position. The only operational difference is that the parking sprag has been disengaged, unlocking the output shaft from the transmission case and allowing it to move freely.
As the engine is running and the crankshaft is rotating, the flexplate and torque converter, which are also bolted to it, are all rotating in a clockwise direction as viewed from the front of the engine. The notched hub of the torque converter is connected to the oil pump’s internal gear, supplying the transmis- sion with oil pressure. As the converter turns, it turns the input shaft in a clockwise direction. As the input shaft is rotating, the front clutch hub-rear clutch retainer and all their associated parts are also rotating, all being directly connected to the input shaft. The power flow from the engine through the front clutch hub and rear clutch retainer stops at the rear clutch retainer. Therefore, no power flow to the output shaft occurs because no clutches are applied. The only mechanism in use at this time is the park- ing sprag (Fig. 3), which locks the parking gear on the output shaft to the transmission case.
Fig.4NeutralPowerflow
1 - PAWL DISENGAGED FOR NEUTRAL 2 - PARK SPRAG 3 - OUTPUT SHAFT 4 - CAM 5 - PAWL
Fig.3ParkPowerflow
1 - PAWL ENGAGED FOR PARK 2 - PARK SPRAG 3 - OUTPUT SHAFT
AUTOMATIC TRANSMISSION - 48RE
21 - 316
AUTOMATIC TRANSMISSION - 48RE (Continued) REVERSE POWERFLOWselector
is moved into
When the gear
the REVERSE position (Fig. 5), the front clutch and the rear band are applied. With the application of the front clutch, engine torque is applied to the sun gear, turning it in a clockwise direction. The clockwise rotation of the sun gear causes the rear planet pin- ions to rotate against engine rotation in a counter- clockwise direction. The rear band is holding the low reverse drum, which is splined to the rear carrier. Since the rear carrier is being held, the torque from the planet pinions is transferred to the rear annulus
DR
gear, which is splined to the output shaft. The output shaft in turn rotates with the annulus gear in a counterclockwise direction giving a reverse gear out- put. The entire transmission of torque is applied to the rear planetary gearset only. Although there is torque input to the front gearset through the sun gear, no other member of the gearset is being held. During the entire reverse stage of operation, the front planetary gears are in an idling condition.
1 - FRONT CLUTCH ENGAGED 2 - OUTPUT SHAFT 3 - LOW/REVERSE BAND APPLIED 4 - INPUT SHAFT
Fig.5ReversePowerflow
5 - OUTPUT SHAFT 6 - INPUT SHAFT 7 - FRONT CLUTCH ENGAGED 8 - LOW/REVERSE BAND APPLIED
AUTOMATIC TRANSMISSION - 48RE
21 - 317
DR AUTOMATIC TRANSMISSION - 48RE (Continued) FIRST GEAR POWERFLOW
When the gearshift lever is moved into the DRIVE position the transmission goes into first gear (Fig. 6). As soon as the transmission is shifted from PARK or NEUTRAL to DRIVE, the rear clutch applies, apply- ing the rear clutch pack to the front annulus gear. Engine torque is now applied to the front annulus gear turning it in a clockwise direction. With the front annulus gear turning in a clockwise direction, it causes the front planets to turn in a clockwise direc- tion. The rotation of the front planets cause the sun to revolve in a counterclockwise direction. The sun gear now transfers its counterclockwise rotation to
the rear planets which rotate back in a clockwise direction. With the rear annulus gear stationary, the rear planet rotation on the annulus gear causes the rear planet carrier to revolve in a counterclockwise direction. The rear planet carrier is splined into the low-reverse drum, and the low reverse drum is splined to the inner race of the over-running clutch. With the over-running clutch locked, the planet car- rier is held, and the resulting torque provided by the planet pinions is transferred to the rear annulus gear. The rear annulus gear is splined to the output shaft and rotated along with it (clockwise) in an underdrive gear reduction mode.
1 - OUTPUT SHAFT 2 - OVER-RUNNING CLUTCH HOLDING 3 - REAR CLUTCH APPLIED 4 - OUTPUT SHAFT
5 - OVER-RUNNING CLUTCH HOLDING 6 - INPUT SHAFT 7 - REAR CLUTCH APPLIED 8 - INPUT SHAFT
Fig.6FirstGearPowerflow
DR
AUTOMATIC TRANSMISSION - 48RE
21 - 318
AUTOMATIC TRANSMISSION - 48RE (Continued) SECOND GEAR POWERFLOWIn DRIVE-SECOND (Fig. 7), the same elements are applied as in MANUAL-SECOND. Therefore, the power flow will be the same, and both gears will be discussed as one in the same. In DRIVE-SECOND, the transmission has proceeded from first gear to its shift point, and is shifting from first gear to second. The second gear shift is obtained by keeping the rear clutch applied and applying the front (kickdown) band. The front band holds the front clutch retainer that is locked to the sun gear driving shell. With the rear clutch still applied, the input is still on the front annulus gear turning it clockwise at engine speed.
Now that the front band is holding the sun gear sta- tionary, the annulus rotation causes the front planets to rotate in a clockwise direction. The front carrier is then also made to rotate in a clockwise direction but at a reduced speed. This will transmit the torque to the output shaft, which is directly connected to the front planet carrier. The rear planetary annulus gear will also be turning because it is directly splined to the output shaft. All power flow has occurred in the front planetary gear set during the drive-second stage of operation, and now the over-running clutch, in the rear of the transmission, is disengaged and freewheeling on its hub.
1 - KICKDOWN BAND APPLIED 2 - OUTPUT SHAFT 3 - REAR CLUTCH ENGAGED 4 - OUTPUT SHAFT 5 - OVER-RUNNING CLUTCH FREE-WHEELING
Fig.7SecondGearPowerflow 6 - INPUT SHAFT 7 - REAR CLUTCH APPLIED 8 - KICKDOWN BAND APPLIED 9 - INPUT SHAFT
AUTOMATIC TRANSMISSION - 48RE
21 - 319
DR AUTOMATIC TRANSMISSION - 48RE (Continued) DIRECT DRIVE POWERFLOW
takes place,
The vehicle has accelerated and reached the shift point for the 2-3 upshift into direct drive (Fig. 8). When the shift the front band is released, and the front clutch is applied. The rear clutch stays applied as it has been in all the forward gears. With the front clutch now applied, engine torque is now on the front clutch retainer, which is locked to the sun gear driving shell. This means that the sun gear is now turning in engine rotation (clock- wise) and at engine speed. The rear clutch is still applied so engine torque is also still on the front
annulus gear. If two members of the same planetary set are driven, direct drive results. Therefore, when two members are rotating at the same speed and in the same direction, it is the same as being locked up. The rear planetary set is also locked up, given the sun gear is still the input, and the rear annulus gear must turn with the output shaft. Both gears are turning in the same direction and at the same speed. The front and rear planet pinions do not turn at all in direct drive. The only rotation is the input from the engine to the connected parts, which are acting as one common unit, to the output shaft.
1 - FRONT CLUTCH APPLIED 2 - OVER-RUNNING CLUTCH FREE-WHEELING 3 - OUTPUT SHAFT 4 - REAR CLUTCH APPLIED 5 - OUTPUT SHAFT
Fig.8DirectDrivePowerflow 6 - INPUT SHAFT 7 - OVER-RUNNING CLUTCH FREE-WHEELING 8 - REAR CLUTCH APPLIED 9 - FRONT CLUTCH APPLIED 10 - INPUT SHAFT
AUTOMATIC TRANSMISSION - 48RE
21 - 320
AUTOMATIC TRANSMISSION - 48RE (Continued) FOURTH GEAR POWERFLOWVEHICLE IS DRIVEABLE
DR
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
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).
(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.
DR AUTOMATIC TRANSMISSION - 48RE (Continued)
AUTOMATIC TRANSMISSION - 48RE
21 - 321
CLUTCH AND BAND APPLICATION CHART
SHIFT LEVER
POSITION
Reverse Drive - First Drive - Second Drive - Third Drive - Fourth Manual Second Manual
First
TRANSMISSION CLUTCHES AND BANDS
OVERDRIVE CLUTCHES
FRONT CLUTCH
FRONT BAND
REAR
CLUTCH
REAR BAND
OVER-
RUNNING CLUTCH
OVER- DRIVE CLUTCH
DIRECT CLUTCH
OVER-
RUNNING CLUTCH
Note that the rear clutch is applied in all forward ranges (D, 2, 1). The transmission overrunning clutch is applied in first gear (D, 2 and 1 ranges) only. The rear band is applied in 1 and R range only.
Note that the overdrive clutch is applied only in fourth gear and the overdrive direct clutch and over- running clutch are applied in all ranges except fourth gear.
For example: If slippage occurs in first gear in D and 2 range but not in 1 range, the transmission overrunning clutch is faulty. Similarly, if slippage occurs in any two forward gears, the rear clutch is slipping.
Applying the same method of analysis, note that the front and rear clutches are applied simulta- neously only in D range third and fourth gear. If the transmission slips in third gear, either the front clutch or the rear clutch is slipping.
If the transmission slips in fourth gear but not in third gear, the overdrive clutch is slipping. By select- ing another gear which does not use these clutches, the slipping unit can be determined. For example, if the transmission also slips in Reverse, the front clutch is slipping. If the transmission does not slip in Reverse, the rear clutch is slipping.
If slippage occurs during the 3-4 shift or only in fourth gear, the overdrive clutch is slipping. Simi- larly, if the direct clutch were to fail, the transmis- sion would lose both reverse gear and overrun braking in 2 position (manual second gear).
If the transmission will not shift to fourth gear, the control switch, overdrive solenoid or related wiring may also be the problem cause.
This process of elimination can be used to identify a slipping unit and check operation. Proper use of the Clutch and Band Application Chart is the key.
Although road test analysis will help determine the slipping unit, the actual cause of a malfunction usu- ally cannot be determined until hydraulic and air pressure tests are performed. Practically any condi- tion can be caused by leaking hydraulic circuits or sticking valves.
Unless a malfunction is obvious, such as no drive in D range first gear, do not disassemble the trans- mission. Perform the hydraulic and air pressure tests to help determine the probable cause.
DIAGNOSIS AND TESTING - HYDRAULIC PRESSURE TEST
Hydraulic test pressures range from a low of one psi (6.895 kPa) governor pressure, to 300 psi (2068
kPa) at the rear servo pressure port in reverse.An accurate tachometer and pressure test gauges are required. Test Gauge C-3292 has a 100 psi range and is used at the accumulator, governor, and front servo ports. Test Gauge C-3293-SP has a 300 psi range and is used at the rear servo and overdrive ports where pressures exceed 100 psi.
Pressure Test Port Locations
Test ports are located at both sides of the transmis-
sion case (Fig. 9).
Line pressure is checked at the accumulator port on the right side of the case. The front servo pressure port is at the right side of the case just behind the filler tube opening.
21 - 322
AUTOMATIC TRANSMISSION - 48RE (Continued)AUTOMATIC TRANSMISSION - 48RE
DR
The rear servo and governor pressure ports are at the right rear of the transmission case. The overdrive clutch pressure port is at the left rear of the case.
† Line pressure at accumulator port should be 54-60 psi (372-414 kPa) with throttle lever forward and gradually increase to 90-96 psi (621-662 kPa) as throttle lever is moved rearward. † Rear servo pressure should be same as line pres-
sure within 3 psi (20.68 kPa).
Test Two - Transmission In 2 Range
This test checks pump output, line pressure and pressure regulation. Use 100 psi Test Gauge C-3292
for this test.(1) Leave vehicle in place on hoist and leave Test
Gauge C-3292 connected to accumulator port.
(2) Have helper start and run engine at 1000 rpm. (3) Move transmission shift lever one detent rear-
ward from full forward position. This is 2 range.
(4) Move transmission throttle lever from full for- ward to full rearward position and read pressure on gauge.
(5) Line pressure should be 54-60 psi
(372-414
kPa) with throttle lever forward and gradually increase to 90-96 psi (621-662 kPa) as lever is moved rearward.Test Three - Transmission In D Range Third Gear
Fig.9PressureTestPortLocations
1 - REAR SERVO TEST PORT 2 - GOVERNOR TEST PORT 3 - ACCUMULATOR TEST PORT 4 - FRONT SERVO TEST PORT 5 - OVERDRIVE CLUTCH TEST PORT
Test One - Transmission In Manual Low
This test checks pump output, pressure regulation, and condition of the rear clutch and servo circuit. Both test gauges are required for this test.
(1) Connect tachometer to engine. Position tachom- eter so it can be observed from driver seat if helper will be operating engine. Raise vehicle on hoist that will allow rear wheels to rotate freely.
(2) Connect 100 psi Gauge C-3292 to accumulator port. Then connect 300 psi Gauge C-3293-SP to rear servo port.
(3) Disconnect throttle and gearshift cables from
levers on transmission valve body manual shaft.
(4) Have helper start and run engine at 1000 rpm. (5) Move transmission shift lever fully forward
into 1 range.
(6) Gradually move transmission throttle lever from full forward to full rearward position and note pressures on both gauges:
This test checks pressure regulation and condition of the clutch circuits. Both test gauges are required for this test.
(1) Turn OD switch off. (2) Leave vehicle on hoist and leave Gauge C-3292
in place at accumulator port.
(3) Move Gauge C-3293-SP over to front servo port
(4) Have helper start and run engine at 1600 rpm
for this test.
for this test.
(5) Move transmission shift lever two detents rear-
ward from full forward position. This is D range.
(6) Read pressures on both gauges as transmission throttle lever is gradually moved from full forward to full rearward position: † Line pressure at accumulator in D range third gear, should be 54-60 psi (372-414 kPa) with throttle lever forward and increase as lever is moved rear- ward.† Front servo pressure in D range third gear, should be within 3 psi (21 kPa) of line pressure up to kickdown point.
Test Four - Transmission In Reverse
This test checks pump output, pressure regulation and the front clutch and rear servo circuits. Use 300
psi Test Gauge C-3293-SP for this test.(1) Leave vehicle on hoist and leave gauge C-3292
in place at accumulator port.
(2) Move 300 psi Gauge C-3293-SP back to rear
servo port.
DR AUTOMATIC TRANSMISSION - 48RE (Continued)
AUTOMATIC TRANSMISSION - 48RE
21 - 323
(3) Have helper start and run engine at 1600 rpm
for test.
(4) Move transmission shift
lever four detents rearward from full forward position. This is Reverse range.
(5) Move transmission throttle lever fully forward then fully rearward and note reading at Gauge C-3293-SP.
(6) Pressure should be 145 - 175 psi (1000-1207
kPa) with throttle lever forward and increase to 230 - 280 psi (1586-1931 kPa) as lever is gradually moved rearward.Test Five - Governor Pressure
This test checks governor operation by measuring governor pressure response to changes in vehicle speed. It is usually not necessary to check governor operation unless shift speeds are incorrect or if the transmission will not downshift. The test should be performed on the road or on a hoist that will allow the rear wheels to rotate freely.
(1) Move 100 psi Test Gauge C-3292 to governor
pressure port.
(2) Move transmission shift lever two detents rear-
ward from full forward position. This is D range.
(3) Have helper start and run engine at curb idle speed. Then firmly apply service brakes so wheels will not rotate.
(4) Note governor pressure: † Governor pressure should be no more than 20.6
kPa (3 psi) at curb idle speed and wheels not rotat-
