Page 395 of 1413

The Automatic Transmission is a combination of a 3-e,ement torque convefter and triple-shaft electfonically controlled
automatic transmission which provides 4 speeds forward and 1 speed reverse. The entire unit is positioned in line with
the engine.
Torque Converter, Gears and Clutches
The torque converter consists of a pump, turbine and stator assembly in a single unit, The torque converter is connected
to the engine crankshaft so they turn together as a unit as the engine turns. Around the outside of the torque converter
is a ring gear which meshes with the starter pinion when the engine is being staned. The entire torque converter assem-
bly serves as a flywheel while transmitting power to the transmission mainshaft.
The transmission has three parallel shafts, the mainshaft. countershaft and sub-shaft. The mainshatt is in line with the
engine crankshaft.
The mainshaft includes the clutches for 1 st, and 2ndl4th, and gears for 3rd. 2nd, 4th, reverse and l st (3rd gear is in-
tegral with the mainshaft, while reverse gear is integral with the 4th gear).
The countershaft includes the 3rd clutch and gears Ior 3rd, 2nd,4th, reverse, lst and parking. Reverse and 4th gears
can be locked to the countershaft at its center, providing 4th gear or reverse, depending on which way the selector is moved.
The sub-shaft includes the lst-hold clutch and gears for 1st and 4th
The gears on the mainshait are in constant mesh with those on the countershaft and sub-shaft. When certain combina-
tions of gears in the transmission are engaged by the clutches, power is transmitted from the mainshaft to the counter-
shaft via the sub-shatt to provide @, E, tr. tr and @ position.
Electronic Control
The electronic control system consists of the Transmission Control Module {TCM), sensors, and 4 solenoid valves. Shift-
ing and lock-up are electronically controlled for comfortable driving under all conditions.
The TCM is located below the dashboard, behind the left side kick panel on the driver's side.
Hydraulic Control
The valve bodies include the main valve body, secondary valve body, regulator valve body. servo body, and lock-up valve
body throuqh the respective separator plates.
They are bolted on the torque converter housing.
The main valve body contains the manual valve, 1-2 shift valve, 2-3 shift valve, Clutch Pressure Cont.ol (CPC) valve,
4th exhaust valve, relief valve, and oil pump gears.
The secondary valve body contains the 4-3 kick-down valve,3-2 kick-down valve,2-3 orifice cont.ol valve, 3-4 shitt
valve, orifice control valve. modulator valve, and servo control valve
The regulator valve body contains the pressure regulator valve. lock-up control valve, torque converter check valve, and
cooler check valve.
The servo bodv contains the servo valve which is integrated with the reverse shift fork, throttle valve B, and accumulators.
The lock-ug valve bodv contains the lock-up shift valve and lock-up timing B valve. and is bolted on the secondary valve
body.
Fluid from the regulator passes through the manual valve to the various control valves.
Shitt Control Mochanism
Input to the TCM i.om various sensors located throughout the car determines which shift control solenoid valve should
be activated.
Activating a shift control solenoid valve changes modulator pressure, causing a shift valve to move. This pressurizes
a line to one of the clutches. engaging that clutch and its corresponding gear.
Lock-up Mechanism
In @ position. in 2nd, 3rd and 4th, and E position in 3rd, pressurized tluid can be drained from the back of the tor-
que converter through an oil passage, causing the lock-up piston to be held against the torque converter cover. As this
takes Dlace, the mainshaft rotates at the same speed as the engine crankshatt. Together with hydraulic control, the TCM
optimizes the timing ol the lock-up mechanism.
The lock-up valves control the range of lock-up according to lock-up control solenoid valves A and B, and throttle valve B
When lock-up control solenoid valves A and B activate, modulator pressure changes. Lock-up control solenoid valves
A and B are mounted on the torque converter housing, and are controlled by the TCM.
(cont'd)
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Page 398 of 1413

Description
Clutches
The four speed automatic transmission uses hydraulically actuated clutches to engage or disengage the transmission gears.
When clutch pressure is introduced into the clutch drum, the clutch piston is applied. This presses the iriction discs and
steel plates together, locking them so they don't slip. Power is then transmitted through the engaged clutch pack tojts hub-mounted gear.
Likewise, when clutch pressure is bled from the clutch pack. the piston releases the friction discs and steel plates, and
they are {ree to slide past each other while disengaged. This allows the gear to spin independently on its shaft, transmit-
ting no power.
1st ClutchThe l st clutch engages/disengages 1st gear, and is located at the end of the mainshaft, just behind the right side cover.
The 1st clutch is supplied clutch pressure by its oil feed pipe within the mainshaft.
1st-hold clutchThe 1st-hold clutch engages/disengages 1st-hold or I Fosition, and is located at the center ol the sub-shaft. The 1st-
hold clutch is supplied clulch pressure by its oil feed pipe within the sub-shait.
2nd ClutchThe 2nd clutch engages/disengages 2nd gear, and is located at the center of the mainshaft. The 2nd clutch is joined
back-to-back to the 4th clutch. The 2nd clutch is supplied clutch pressure through the mainshaft by a circuit connected
to the regulator valve body.
3rd Clutch
The 3rd clutch engages/disengages 3rd gea.. and is located at the end oJ the countershaft, opposite the right side cover.
The 3rd clutch is supplied clutch pressure by its oil feed pipe within the countershaft,
4th clurch
The 4th clutch engages/disengages 4th gear. as well as reverse gear, and is located at the center of the mainshaft.
The 4th clutch is joined back-to-back to the 2nd clutch. The 4th clutch is supplied clutch pressure by its oil feed pipe
within the mainshalt.
One-way Clutch
The one-way clutch is posjtioned between the parking gear and 1st gear. with the parking gear splined to the counter-
shaft. The 1st gear provides the outer race, and the parking gear provides the inner race surface. The one-way clutch
locks up when power is transmitted from the mainshaft 1st gear to the countershaft lst ggel _The 1st clutch and gears remain engaged in the 1st. 2nd. 3rd, and 4th gear ranges in the @, E or E position.
However, the one-way clutch disengages when the 2nd. 3rd, or 4th clutches/gears are applied in the E, lD.l o, Eoosttton.
This is because the increased rotational speed of the gears on the countershaft over-ride the locking "speed range" of
the one-way clutch. Thereafter, the one-way clutch free-wheels with the lst clutch still engaged.
COUNTERSHAFT 1ST GEAR
FREE
:>
LOCKS
aF
NOTE:View trom right side cover side.
14-6
Page 415 of 1413
Hydraulic Control
The valve bodies include the main valve body, secondary valve body, regulator valve body, servo body and lock-up valve
body.
The oil pump is driven by splines behind the torque converter which is attached to the engine. Oil flows th.ough the
regulator valve to maintain specified pressure through the main valve body to the manual valve, directing pressure to
each of the clutches,
SHIFT CONTROL SOLEIIOIDVALVE ASSEMBLY
RTGHT SIDE COVER
LOCK.UP VALVE BODY
VALVE BODY
REGULATOR VBODY
SOLENOID VALVEASSEMBLY
4<.__i: )o.-
OIL PUMP GEARS
14-23
Page 416 of 1413
Description
Hydraulic Control (cont'dl
Ragularol Valve Body
The .egulator valve body is located on the main valve body. The regulator valve body consists of th€ regulator valva,
toroue converter check valve, cooler check valve, and lock-up contlol valve.
REGULATOR VALVE
REGULATOR VALVEBODY
COOLER CHECK VALVE
LOCT.UP CONTROI. VALVE
TONOUE COI{VERTEBCHECK VALVE
Lock-up Valvo Body
The lock-up valve body with the lock-up shilt valve and lock-up timing B valve is located on th€ regulator volvs body.
LOCK.UP SHIFT VALVE
TIMITG B VALVE
14-24
Page 418 of 1413
Description
Hydraulic Control (cont'dl
Main Valvo Body
The manual valve, 1-2 shift valve, 2-3 shift valve. 4th exhaust valve. CPC valve, and relief vatve are all assembled inthe main valve body,
The primary function of this valve body is switching oil passages on and off and controlling the hydraulic pressure gotngto the hydraulic control system.
4TH EXHAUST VALVECPC VALVE
RELIEF VALVE
MANUAL VALVEMAIN VALVE BODY
S€condary Vslve Body
The secondary valve body is located on the main valve body. The 3-2 kick-down valve, 4-3 kick-down valve. 2-3 orificecontrolvalve. orifice controlvalve, 3-4 shift valve, modulator valve, and servo control valve are assembled in the secon-da.y valve body.
ORIFICE COIITROLVALVE2-3 ORIFICE CONTBOL VALVE
3.4 SHIFT VALVE
VALVE BODY
MOOULACOITTROL VALVE
1.2 SHIFT VALVE
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Page 419 of 1413
S6rvo Body
The servo bodv is located on the secondary valve body.
The servo valve is integrated with the shiit fork shatt, throttle valve B. and accumulator pistons, which are all assembled
in the servo bodv.
SERVO VALVE/SHIFT FORK SHAFT
THROTTLE VALVE BSERVO BODY
Accumulator Pislons
The accumulator pistons are assembled in the servo body and right side cover. The l st-hold clutch accumulator piston
is in the right side cover, and the 1st, 2nd 3rd, and 4th accumulator pistons are assembled in lhe servo body.
RIGHT SIDE COVER
THROTTLE LONG VALVE
1ST-HOLD ACCUMULATOR
4TH ACCUMULATOR
IST ACCUMUI-ATOR
2ND ACCUMULATOR PISTON3RD ACCUMULATOR PISTON
14-27
Page 459 of 1413
Disconnoct the 22P connectortrom the TCM. Connecr tho T€stHarness "D" connector to thewhe harness onlv, not to the TCMlsee page '14-49).
Check for continuitv betweenbody ground and 017 terminaland D15 terminsl individually.
Rgpllr short in BLU/GRI{ otBLU|/EL wlro b€twgon Dl7 andDl5 torminsla and ths countar-rhaft apo€d sengor.
Reconnect the countershaftsDe00 sensor connector.
Msasure the rgsistance betweenD 1 7 and 015 terminals.
Rgpair looa6 ta.minsl or opon in8LU/GRN o. 8LU/YEL wiro bo-trvaon D'17 and D15 tormindgand tho count6rlhafl !p6gd!€ntor,
ls the r€sistance 4OO-600 07
Ch6ck for looaa TCM conn6cto..ll nocaslrry, aubrlitut6 a known-good TCM a.d .6ch.ck.
(cont'd)
4-67
Page 464 of 1413
Electrical Troubleshootang
Troubleshooting Flowchart (cont'd)
From page '14-71
TCM 22P CONNECTOR
Disconnect the 22P connectorslrom the TCM and ECM.
Check for continuity between theD3 {LT GRN) terminal ol the TcM22P connecror and the D8 ILTGRN) terminal of the ECM 22Pconnector.
Ropai. opon In LT GRN rvi.a b.-twoon tho TCM and ECM.
Check lor continuity between theLT GRN wire and body ground.
Ropair short lo body ground inLT GRN wir6.
Ch€ck lor loos6 TCM and ECMconnectors, lf necessary, aubari-tute a known-good TCM andrccheck.
NOTE: View from wire side.
ECM 22P COiINECTOR
14-72