Page 712 of 2189

Description
Lock-up System (cont'd)
TOROUE CONVERTER
In B.rl position, in 3rd and 4th, and lDl_- position in 3rd.pressurized fluid is drajned from the back of the torqueconverter through a fluid passage. causing the lock-uppiston to be held against the torque convener cover. Asthis takes place, the mainshaft rotates at the same speedas the engine crankshaft, Together with the hydrauliccontrol, the PCM optimized the timing of the lock_upsystem. Under certain conditions, the lock_up clutch isapplied during deceleration, in 3rd and 4th gear.
The lock-up system controls the range of lock_up accord_ing to lock-up control solenoid valves A and B. and thelinear solenoid. When lock-up control solenoid valves Aand B activate, modulator pressure changes. Lock_upcontrol solenoid valves A and B and the linear solenoidare mounted on the outside of the torque converterhousing. and are controlled by the pclvl.
Lock-up Conditions/Lock-up Control Solenoid Valves/Linear Solenoid Pressure
MODULATOR PRESSURE
.-- LINEAR SOLENOID PRESSURE
LOCK.UP CONTROL. VALVE
LOCK.UP CONTROLSOLENOID VALVELock-up
Conditions
Lock-up Control
Solenoid ValveLineal
Solenoid
PressureAB
Lock-up OFFOFFOFFHig h
Lock-up. HalfONDuty operation
OFF - ON
Lock-up. FullONONHigh
Lock-up
during
decelerationONDuty operation
OFF * ONLowTOROUE CONVERTERCHECI( VALVE
RELIEF VAI-VE
LOCK.UP TIMINGVALVE
^ r______rr r cooLER RELTEF VALVE
t'-
14-34
ATF PUMP
Page 713 of 2189
I
TOROUE CONVERTER
No Lock-up
. Lock-up Control Solenoid Valve A: OFF
. Lock-up Control Solenoid Valve B: OFF
. Linear Solenoid Pressure: High
The pressurized fluid regulated by the modulator works
on both ends of the lock-up shift valve. Under this condi-
tion, the pressures working on both ends of the lock-up
shift valve are equal, the lock-up shift valve is moved to
the right side by the tension of the valve spring alone.
The fluid from the ATF pump will flow through the left
side of the lock-up clutch to the torque convener; that is,
the lock-up clutch is in OFF condition.
NOTE: When used, "left" or "right" indicates direction
on the hydraulic circuit.
MOOULATOR PRESSURE
LINEAR SOLENOIO PRESSURE
(cont'd)
LOCK.UP CONTROLSOLENOID VALVE
RELIEF VALVE
LOCK-UP TIMINGVALVE
9 L ] I COOLER RELIEF VALVE
ATF PUMP
14-35
Page 715 of 2189

TOROUE CONVERTER
Full Lock-up
. Lock-up Control Solenoid Valve A: ON
. Lock-up Control Solenoid Valve B: ON
o Linear Solenoid Pressure: High
When the vehicle speed further increases. the linear
solenoid pressure is increased to high in accordance
with the linear solenoid controlled bv the PCM.
The lock-up timing valve overcomes the spring force
and moves to the left side. Also, this valve closes the
fluid port leading to the left side of the lock-up control
Under this condition. the modulator pressure in the left
side of the lock-up control valve had already been
released by the lock-up control solenoid valve B; the
lock-up control valve js moved to the left side. As this
takes place, the torque converter back pressure is
released fully. causing the lock-up clutch to be engaged
fully.
NOTE: When used, "|eft" or "right" indicates direction
on the hvdraulic circuit.
MODULATOR PRESSURE
LINEAR SOLENOIO PRESSURE
{cont'd)
LOCK.UP CONTROLSOLENOID VALVE
RELIEF VALVE
LOCK.UP TIMINGVALVE
'r ,-.r' cooLER RELTEF vALvE
ATF PUMP
14-37
Page 790 of 2189

Symptom-to-Component Chart
Hydraulic System (cont'dl
G.
n,
set idle rpm in gear to specified idle speed. lf still no good, adjust motor mounts as outlined in enginesection of this manual.
lf the clutch pack is seized or is excessively worn. inspect the other clutches for wear, and check the orificecontrol valves, CPC valve and linear solenoid for free movement.
lf the linear solenoid is stuck, inspect the clutches for wear.
lmproper alignment or main valve body and torque converter housing may cause ATF pump seizure. Thesymptoms are mostly an rpm-related ticking noise or a high-pitched squeak.
lf the l st clutch feed pipe guide in the end cover is scored by the mainshaft, inspect the ball bearing forexcessive movement in the transmission housing. lf oK, replace the end cover as it is dented. The o-rinounder the guide is probably worn.
Replace the mainshaft if the bushing for the 4th feed pipe is loose or damaged. lf the 4th feed pipe is danFaged or out of round, replace the right side cover.
Replace the mainshaft if the bushing for the 1st feed pipe is loose or damaged. lf the 1st feed pipe is darn-aged or out of round, replace it.
A worn or damaged sprag clutch is mostly a result of shifting the transmission inthe wheels rotate in reverse, such as rocking the vehicle in snow.
or E position while
Inspect for damage and wear:
1. Reverse selector gear teeth chamfers.
2. Engagement teeth chamfers of countershaft 4th and reverse gear.
3. Shift fork for scuff marks in center.
4. Differential pinion shaft for wear u nder pin ion gears.
5. Bottom of 3rd clutch for swirl marks.
Replace items 1,2,3 and 4 if worn or damaged. lf transmission makes a clicking, grinding orwhirring noise,also replace mainshaft 4th gear, reverse idler gear. and countershaft 4th gear in addition to 1, 2, 3 or 4.lf differential pinion shaft is worn, overhaul differential assembly, and replace ATF strainer, and thoroughlyclean transmission, flush torque converter, cooler and lines.lf bottom of 3rd clutch is swirled and transmission makes gear noise, replace the countershaft and final drivengear.
Be very careful not to damage the torque converter housing when replacing the main ball bearing, you
may also damage the ATF pump when you torque down the main valve body. This will result in ATF pumpseizure if not detected. Use the oroper roors.
Install the main seal flush with the torque converter housing. lf you push it into the torque converterhousing until it bottoms out, it will block the fluid return passage and result in damage.
See flushing procedure, page 14-187 and 188.
lf the large clutch piston O-ring is broken, inspect the piston groove for rough machining.
lf the l-2 shift valve is stuck closed, the transmission will not upshift. lf stuck open, the transmission hasno 1st gear.
lf the znd orifice control valve is stuck. inspect the 2nd and 3rd clutch oacks for wear.
lf the 3-4 orifice control valve is stuck, inspect the 3rd and 4th clutch oacks for wear.
lf the clutch pressure control valve is stuck closed, the transmission will not shift out of 1st gear.
lf the ATF strainer is clogged with particles of steel or aluminum, inspect the ATF pump and differentialpinion shaft. lf both are OK and no cause for the contamination is found, replace the torque converter.
Inspect the frame for collision damage.
14-112
Page 794 of 2189

Stall Speed
Test
CAUTION:
. To prev€nt transmission damage, do not t6st stall speed for more than ro sgconds at a time.. Do not shift the levor while raising the engine speed.. Bo sule lo remove the pressure gauge betoro testing stall speed.
'1. Engage the parking brake, and block the front wheels.
2. Connect a tachometer to the engine, and start the engine.
3. Make sure the Ay'C switch is OFF.
4. After the engine has warmed up to normal operating temperature (the radiator fan comes on). shift into E position.
5. Fully depress the brake pedal and accelerator for 6 to g seconds, and note engine speed.
6. Allow two minutes for cooling, then repeat the test in @ and @ positions.
NOTE:
. Stall speed tests should be used for diagnostic purposes only,. Stall speed should be the same in o., E and E positions.
Stall Spsed RPM:
Specification: 2.700 rpm
Service Limit: 2,550 - 2,850 rDm
TROUBLEPROBABLE CAUSE
. Low fluid level or ATF pump outDur. Clogged ATF strainer. Pressure regulator valve sluck closeo. Slipping clutch
. Slippage of 4th ctutch
. Slippage of 2nd clutch
. Slippage of lst clut"tr or. t"t g""io*-*"y "lut"h
Stall rpm high in D., E and E positions
Stall rpm high in El position
Stall rpm high in E posirion
Stall rpm high in E position
Stall rpm low in LDa . El and E positrons. Engine output low. Torque converter one-way clutch slipping
14-116
Page 797 of 2189

Pressure Testing
@I While testing, be caroful of th€ rotating front wheels.
. Make sure lifts, iacks, and satoty stands are placod properly (see section 1)'
CAUTION:
. Beforo iesting, be sure the transmission fluid is tilled to tho proper level'
. Warm up tho engine before testing'
1. Raise the vehicle (see section 1).
2. Warm up the engine, then stop the engine and connect a tachometer'
3. Connect the oil pressure gauges to each inspection hole.
TOROUE: 18 N.m (1.8 kgf'm, 13 lbnft)
cAUTloN: connact the oil pressuro gauges securely; be suro not to allow dust and other foreign Parlicles to entel
the inspestion holos'
A/T OIL PRESSURE GAUGESET w/PANEL07t06 - 0020400
A/T LOW PRESSURE GAUGE
SET WPANEL07406 - 0070300
A/T OIL PRESSURE HOSEADAPTER07Mru - PY0120(4 requiJedl
A/T OIL PBESSURE HOSE
2210 mmOTMAJ - PY4{)llA
14 roquircdl
Start the engine, and measure the respective ptessure as follows'
a Line Pressure
. 1st Clutch Pressure
. 2nd,3rd and 4th Clutch Pressure
Install a new washer and the sealing bolt in the inspection hole. and tighten to the specified torque'
TOROUE: l8 N.m (1.8 kgf'm,13lbf'ft)
NOTE: Do not reuse old sealing washers; always replace washers'
(cont'd)
14-119
Page 798 of 2189
Pressure Testing
(cont'd)
Line Pressure/1st Clutch Pressurc Measurement
1. Set the parking brake, and btock both rear wheels securely.
2. Start the engine, and run it at 2,OOO rpm.
3. Shift to N or E position, then measure line pressure.
NoTE: Higher pressure may be indicated if measurements are made in shift lever positions other than @ or @ positron.
4. Shift to tq;l position, hold the engine at 2,000 rpm, and measure 1st crutch pressure.
1ST CLUTCH PRESSUREINSPECTION HOLE(Marked with "1")
LOCK.UP CONTROLSOLENOID VALVE A/8ASSEMBLY
VALVE A/B ASSEMBLY
PRESSURESHIFT LEVER
POS|TtONSYMPTOMPROBABLE CAUSEFLUID PRESSURE
StandardService Limit
LineN orENo (or low)
lrne pressureTorque converter,
ATF pump, pres-
sure regutator.
torque converter
check valve
830 - 880 kPa
{8.5 - 9.0 kgf/cm?,
120 - 130 psi)
780 kPa(8.0 kgf/cm' , 110 psi)
1st ClutchD;lNo or low 1st
pressure
1st Clutch
\
14-120
Page 799 of 2189
2nd, 3rd and 4th Clutch Pressure Measurement
1. Set the parking brake, and block both rear wheels securely'
2. Start the engine, and run it the engine at 2,000 rpm'
3. Shift to E position, then measure 2nd clutch pressure
4. Shiftto El position, then measure3rd clutch pressure
5. Shift to E position, then measure 4th clutch pressure'
6. Shift to E position, then measure 4th clutch pressure'
INSPECTION HOI'E(Marked with "3")
2ND CLUTCH PR€SSURE
INSPECTION HOLE
FLUID PRESSURE
standard I sorviqe LimitPRESSURESHIFT LEVER
POStT|()NSYMPTOMPROBABLE CAUSE
2nd ClutchtrNo or low 2nd
pressure
2nd Clutch800 - 850 kPa
(8.2 - 8.7 kgflcm' ,
120 - 120 psi)
760 kPa
(7.7 kgf/cm' , 110 Psil
3rd ClutchtrNo or low 3rd
pressure
3rd Clutch8' 10 - 860 kPa
(8.3 - 8.8 kgt/cm',
120 - 130 psi)
760 kPa
(7.8 kgt/cm', 110 Psi)
4th clutchp.lNo or low 4th
presSure
4th clurch
EServo Valve or 4th
Clutch
1+121