Description
Hydraulic Control
The hydraulic control system is controlled by the ATF pump, valves, accumulators, and electronically controlled solenoids.
The ATF pump is driven by splines on the end of the torque converter which is aftached to the engine. Fluid from the ATF
pump flows through the regulator valve to maintain specified pressure, through the main valve body, to the manual valve,
directing pressure to each clutch. The valve body includes the main valve body, the regulator valve body, the lock-up
valve body, the secondary valve body, the servo body, the linear solenoid, the shift control solenoid valve Ay'B assembly,
and the lock-up control solenoid valve A/B assembly. The shift control solenoid valve A,/B assembly and the linear
solenoid are bolted on the outside of the transmission housing. The lock-up control solenoid valve A,/B assembly is bolted
on the outside of the torque converter housing.
LINEAR
SHIFT CONTROLSOLENOID VALVE A/BASSEMBLY
SECONDARY VALVEBODY
REGULATORVALVE BOOY
VALVE BODY
SOLENOID VALVE A/BASSEMELY
N
ATF PUMP GEARS
14-24
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Description
Hydraulic Flow (cont'dl
lll Position
As the engine turns, the ATF pump starts to operate. Automatic transmission fluid (ATF) is drawn from (99) and dis-charged into (1). Then, ATF flowing from the ATF pump becomes line pressure ('l). Line pressure (1) js regulated by theregulator valve. Torque converter inlet pressure {92) enters (94) of the torque conveTter through the lock-up shift valve anddischarges into (90) The torque converter check valve prevents torque converter pressure from rising. Under this condi-tion, hydraulic pressure is not applied to the clutches.
NOTE;
. When used. "|eft" o. "right" indicates direction on the hvdraulic circutt.. The hydraulic circuit shows the '97 - 98 models {7 positions}; the '99 - 00 models (6 positions) is similar.
'lF'.j.l
14-30
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Lock-up System
TOROUE CONVERTER
In E position ('97 - 98 models) and in E position ('99 -
OO models) (3rd and 4th), and E position ('97 - 98 mod-
els) and in E position with Over-Drive (O/D) is OFF (by
pressing the O/D switch) ('99 - 00 models) (3rd), pressur-
ized fluid is drained from the back of the torque convert-
er through a fluid 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 th8
engine crankshaft. Together with the hydraulic control,
the PCM optimizes the timing of the lock-up system.
Under certain condltions. the lock-up clutch is appli€d
during deceleration, in 3rd and 4th gear.
The lock-up system controls the range of lock-up sccord-
ing to lock-up control solenoid valves A and B, and ths
linear solenoid. 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 out-
side of the torque converter housing, and the linear
solenoid is mounted on the transmission housing. They
are controlled bv the PCM.
The table below shows the lock-up conditions for lock-up
control solenoid valves and linear solenoid pressure.
LINEAR SOLENOID PRESSURE
(cont'd)
LOCK.UP CONTROL' VALVE
LOCK.UP CONTROLSOLENOID VALVE
AB
MODULATORPf,ESSURE
MAINSHAFT
COUNTERSHAFT
SUB.SHAFT
Lock-up
Conditions
Lock-up Conirol
Solenoid valveLinaal
Solenoid
PrgssulsAB
Lock-up OFFOFFOFFHigh
Lock-up, HalfONDuty operation
OFF - ONLow
Lock-up, FullONONHigh
Lock-up
during
deceleration
ONDuty operation
OFF - ON
RELIEF VALVE
LOCK'UP TIMINGVALVE
COOLER RELIEF VALVE
ATF COOLERATF STRAINER
ATF PUMP
14-39
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Mai nshaft /Cou ntershaft
Linear Solenoid AssemblySpeed Sensors
Replacement
'1. Remove the mounting bolts and the linear solenoid
assemblY.
Clean the mounting surfaceand fluid passages.
6x1.0mm12 N.m (1.2 kg{.m.8.7 tbtftl
@
@
GASKET
Clean the mounting surface and fluid passage of the
linear solenoid assembly and transmission housing.
Install a new linear solenoid assemblv with a new
gasket. Do not pinch the gasket during installation,
and make sure it is installed properly in the mount-
ing groove of the linear solenoid.
Check the linear solenoid connector for rust. dirt, or
oil, then connect it securelv.
14-138
Replacement
1. Remove the 6 mm bolt and the countershaft sDeed
sensor from the end cover.
\
5x1.0mm12 N.m 11.2 kgf.m, COUNTERSHAFT8.7 rbf.frl SPEED SENSOR
O.RINGReplace.
12 N'm 11.2 kgl.m,8.7 tbf.ftl
Remove the 6 mm bolt and the mainshaft speed
sensor from the transmission housing.
Replace the O-ring with a new one before installing
the countershaft speed sensor or the mainshaft speed
sensor,
6x1.0mm
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The following symptom can be caused
by improper repair or assemblYCheck these items
. lmproper clutch clearance
. lmproper gear clearance
One-way (sprag) clutch installed upside down
Park lever installed upside down
Shift fork bolt not installed
Vehicle creeps in N position.
Vehicle does not move in E, [D.lj, or E
position.
Transmission locks up in E position.
Excessive drag in transmission.ATF pump binding and seizure
Use proper tools when replacing the ATF pump gears, and be careful
to damage the ATF pump when torque down the main valve body.
Check that the shift fork bolt is installed on the shift fork shaft
not
Excessive vibration, rpm related.Torque converter not fully seated in ATF pump
Reverse selector hub installed upside downNoise only with wheels moving.
Mainshaft oil seal po9s out.Mainshaft oil seal improperly installed
lnstallthe mainshaft oil seal tlush with the torque converter housing lf
the mainshaft oil seal is installed into the torque converter housing until
it bottoms. it will block the fluid return passage and result in damage
Various shifting problems.. Springs improperly installed
. Valves improperly installed
Harsh upshift.Check valve balls not installed
(cont'd)
4-155
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Symptom-to-Com ponent Chart
Hydraulic System (cont'd)
NOTES
See flushing procedure, page l4-264 and 265,
BSet idle rpm in gear to specified idle speed. lf still no good, adjust motor mounts as outlined in enginesection of this manual.
clf the large clutch piston O-ring is broken, inspect the piston groove for rough machining.
Dlf the clutch pack is seized or is excessively worn. inspect the other clutches fot 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.
lf the 1-2 shift valve is stuck closed. the transmission will not upshift. lf stuck open, the transmission hasno lst gear.
Hlf the 2nd orifice control valve is stuck, inspect the 2nd and 3rd clutch Dacks for wear.
lf the 3-4 orifice control valve is stuck, inspect the 3rd and 4th clutch packs for wear.
Jlf the clutch pressure control valve is stuck closed. the transmission will not shift out of lst gear.
Klmproper alignment of 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.
Llf 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.
Mlf the lst 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.
N' Replace the mainshaft if the bushing for the 4th feed pipe is loose or damaged, lf the 4th feed pipe is darrFaged or out of round. replace the end cover.' Replace the mainshaft if the bushing for the l st feed pipe is loose or damaged. lf the 1st feed pipe is dam-aged or out of round, replace it.
oA worn or damaged sprag clutch is mostly a result of shifting the transmission in E!. E, or E positionwhile the wheels rotate in reverse. such as rocking the vehicle in snow.
PInspect the frame for collision damage.
lnspect for damage and wear:
l. 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 under pinion 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, or whirring 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, replace ATF strainer, and thoroughly cjeantransmission, flush torque converter. cooler, and lines,lf bottom of 3rd clutch is swirled and transmission makes gear noise. replace the countershaft and final drivenoear,
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 Drooer tools.
SInstall 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.
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Road Test
NOTE: Warm up the engine to normal operating temperature (the radiator tan comes on).
1. Before testing, check the transmission fluid level, see page 14-160.
2. Apply the parking brake and block the wheels. start the engine, then shift to E {'97 - 98) or E {'gg - 00) position
while pressing the brake pedal. Press the accelerator pedal and release it suddenly. The engine should not stall.
3. Repeat same test in E position ('97 - 98 models).
4. Test-drive the vehicle on a flat road in the E or E position. Check that the shift points occur at approximate speeds
shown on a flat road. Also check for abnormal noise and clutch slippage.
Throttle position sensor voltage represents the throttle opening. Monitor it with the Honda PGM Tester or as follows:
a. Unbolt the PCM for road testing; reJer to page 14-58.
b. Set the digital multimeter to check throttle position sensor voltage between these terminals on the PCM:
. '97 Model: Between terminals D'! (+) and A9 (-) or A22 {-}
. '98 - OO Models; Between terminals C27 (+) and 820 (-) or 822 {-)
BACKPROBE ADAPTER
BACKPROBE SETorsAz - 001moA(two roquircdl
STACKING PATCH
CORD
DIGiTAL MULTIMETER
{Comm€rcirllY .vailablc}KS-AHM-32-003,or equival.nt
'97 Model:PCM CONNECTORS
'98 - 0O Models:
A l32Pt
Wire side of female terminals
PCM CONNECTORS
B {25Pt c l31P}
(cont'd)
LGl (BRN/BLK)
'. //B 1 l'o ti , jl. to a 2r / / 11111t1.t nait la t1 t213tr / t6t, tl / / / / 1 3 / 10n v
t-'a:IM-&E -Llfiffi-fl)\"".'E
Wire side ot female termanals14-157
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Stall Speed
Test
CAUTION:
. To prevent transmission damage, do not te3t stall speed for mors than 10 s€€onds at a time'
. Do not shift the lever while raising th€ engine spsed.
. Be sure to remove tho pressuro gauge bofore testing stall speed,
1. Before testing, check the transmission fluid level, s€e page 14-160.
2. Engage the parking brake and block all four wheels
3. Connect the tachometer, and start the engane.
4. Make sure the Ay'C switch is OFF
5. After the engine haswarmed upto normal operating temperature (the radiator fan comes on),shiftinto@ position.
6. Fully press the brake pedal and accelerator for 6 to 8 seconds, and note engine speed '
j. A|ow 2 minutes for cooling, then repeat the test in E, E ('97 - 98). E {'99 - 00}, and E positions. Stall speed should
be the same in E, E, E, tr. and E positions
Stall Speed rpm:
Specitication: 2,550 rpm
S€rvice Limit: ?,400 - 2.700 rpm
TROUBLEPROBAELE CAUSE
Stall rpm high in El, E, E, E and E
positions
ATF pump output is low
Clogged ATF strainer
Pressure regulator valve stuck closed
Slipping clutch
Stall rpm high in E positionSlippage of 1st clutch, 1st-hold clutch, or 1st gear one-way clutch
Stall rpm high in E positionSlippage of 2nd clutch
stall rpm high in E! or E positionSlippage of 1st clutch or 1st gear one-way clutch
Stall rpm high in E positionSlippage of 4th clutch
Stall rpm low in [dd, E. E, E, ana E
positions
. Engine output low
. Torque converter one-way clutch slipping
14-159
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