ACURA RL KA9 1996 Service Repair Manual

Hydraulic Flo w (cont'd )
or Positio n
1 .
1s t Gea r
The flo w o f flui d throug h th e torqu e converte r circui t i s th e sam e a s in position . Th e lin e pressur e (1) flow s throug h
the manua l valve , th e modulato r valve , th e lin e pressur e contro l valv e an d th e throttl e valve . Th e lin e pressur e (1 )
become s th e modulato r pressur e (6 ) a t th e modulato r valve , an d th e lin e pressur e (4 ) a t th e manua l valve . Th e modula -
to r pressur e (6 ) flow s t o th e lef t end s o f th e 1- 2 shif t valv e an d th e 3- 4 shif t valv e becaus e shif t solenoi d valv e A is
turne d OF F an d B is turne d O N b y th e PCM . Th e 1- 2 shif t valv e is move d t o th e righ t side , an d uncover s th e por t t o
allo w th e 1s t clutc h pressur e
(10) to th e 1s t clutch . Th e 1s t clutc h pressur e (10 ) i s applie d to th e 1s t clutch , consequent -
ly, th e vehicl e wil l mov e a s th e engin e powe r i s transmitted . I n o r position , th e 1st-hol d clutc h pressur e i s no t
applie d to th e 1st-hol d clutc h becaus e th e manua l valv e cover s th e por t leadin g to th e 1st-hol d clutch .
NOTE:
• Whe n used , "left " o r "right " indicate s directio n o n th e hydrauli c circuit .
• Th e hydrauli c circui t i s fo r
'96 - '9 8 models . O n '99 - 0 1 models , th e 2n d accumulato r i s different .
Descriptio n
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2. 2nd Gear

As the speed of the vehicle reaches the prescribed value, shift solenoid valve A is turned ON by means of the PCM.

Shift solenoid valve B remains ON. The modulator pressure (6A) in the left end of the 1-2 shift valve is released by turn-

ing shift solenoid valve A ON. The 1-2 shift valve is moved to the left side and uncovers the port to allow the line pres-

sure (5) to the 2nd clutch. The line pressure (5) becomes the 2nd clutch pressure (20) at the orifice. The 2nd clutch pres-

sure (20) is applied to the 2nd clutch, and the 2nd clutch is engaged.

Hydraulic pressure also flows to the 1st clutch. However, no power is transmitted because of the one-way clutch.

NOTE:

• When used, "left" or "right" indicates direction on the hydraulic circuit.

• The hydraulic circuit is for '96 - '98 models. On '99 - 01 models, the 2nd accumulator is different.ProCarManuals.com

Description
Hydraulic Flo w (cont'd )
or Positio n
3. 3r d Gea r
As th e spee d o f th e vehicl e reache s th e prescribe d value , shif t solenoi d valv e B is turne d OF F b y mean s o f th e PCM .
Shif t solenoi d valv e A remain s ON . Th e modulato r pressur e (6B ) flow s t o th e righ t end s o f th e 1- 2 shif t valv e an d th e 2 -
3 shif t valve . Th e 2- 3 shif t valv e i s move d t o th e lef t sid e b y th e modulato r pressur e (6B) . Th e 2- 3 shif t valv e uncover s
th e por t t o allo w th e lin e pressur e (5 ) t o th e 3- 4 shif t valv e a s thi s valv e is move d t o th e lef t side . Th e lin e pressur e (5' )
become s th e 3r d clutc h pressur e a t th e 3- 4 shif t valve . Th e 3r d clutc h pressur e (30 ) i s applie d to th e 3r d clutch , an d th e
3r d clutc h is engaged .
Hydrauli c pressur e als o flow s t o th e 1s t clutc h an d 2n d clutch . However , n o powe r i s transmitte d becaus e o f th e one -
wa y clutches .
NOTE:
• Whe n used , "left " o r "right " indicate s directio n o n th e hydrauli c circuit .
• Th e hydrauli c circui t i s fo r '9 6 - '9 8 models . O n '9 9 - 0 1 models , th e 2n d accumulato r i s different .
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Position

4. 4th Gear

As the speed of the vehicle reaches the prescribed value, shift solenoid valve A is turned OFF by means of the PCM.

Shift solenoid valve B remains OFF. The modulator pressure (6A) flows to the right end of the 3-4 shift valve and the

left end of the 1-2 shift valve. The modulator pressure (6A) in the left end of the 1-2 shift valve equals the modulator

pressure (6B) in the right end of the 1-2 shift valve, so the 1-2 shift valve remains in the left side by the tension of the

valve spring. The 3-4 shift valve is moved to the left side by modulator pressure (6B). The 3-4 shift valve covers the port

leading to the 3rd clutch and uncovers to the 4th clutch as this valve is moved to the left side. The line pressure (5')

from the 2-3 shift valve becomes the 4th clutch pressure (40) at the 3-4 shift valve. The 4th clutch pressure (40) is

applied to the 4th clutch, and the 4th clutch is engaged.

Hydraulic pressure also flows to the 1st clutch and 2nd clutch. However, no power is transmitted because of the one-

way clutches.

NOTE:

• When used, "left" or "right" indicates direction on the hydraulic circuit.

• The hydraulic circuit is for '96 - '98 models. On '99 - 01 models, the 2nd accumulator is different.

THROTTLE VALVEProCarManuals.com

Description
Hydraulic Flo w (cont'd )
Position
The flo w o f flui d throug h th e torqu e converte r circui t i s th e sam e a s in position .
Th e lin e pressur e (1 ) become s th e modulato r pressur e (6 ) a t th e modulato r valve , an d th e lin e pressur e (3 ) a t th e manua l
valve.
The modulato r pressur e (6 ) flow s t o th e righ t end s o f th e 1- 2 shif t valv e an d 2- 3 shif t valv e becaus e shif t solenoi d valv e A
i s turne d O N an d B is turne d OF F b y th e PCM , an d thos e valve s ar e move d to th e lef t side .
Th e lin e pressur e (3 ) flow s t o th e 1- 2 shif t valv e an d it become s th e revers e clutc h pressur e (50) . Th e revers e clutc h pres -
sur e (50 ) i s applie d to th e revers e clutch , an d th e revers e clutc h is engaged .
Revers e Inhibito r Contro l
When th e positio n i s selecte d whil e th e vehicl e i s movin g forwar d a t speed s ove r 6 mp h (1 0 km/h) , th e PC M output s th e
1s t signa l t o shif t solenoi d valve s A an d B ; shif t solenoi d valv e A is turne d OFF , shif t solenoi d valv e B is turne d ON . Th e 1 -
2 shif t valv e is move d to th e righ t sid e an d cover s th e por t t o sto p lin e pressur e (3 ) t o th e revers e clutch . Th e lin e pressur e
(3 ) i s no t applie d t o th e revers e clutch , an d th e revers e clutc h pressur e (50 ) i s no t applie d to th e revers e clutch , a s a result ,
powe r i s no t transmitte d i n th e revers e direction .
NOTE:
• Whe n used , "left " o r "right " indicate s directio n o n th e hydrauli c circuit .
• Th e hydrauli c circui t i s fo r '9 6 - '9 8 models . O n '9 9 - 0 1 models , th e 2n d accumulato r i s different .
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Position

The flow of fluid through the torque converter circuit is the same as in position.

The line pressure (1) is intercepted by the manual valve. Hydraulic pressure is not supplied to the clutches, and power is

not transmitted.

NOTE:

• When used, "left" or "right" indicates direction on the hydraulic circuit.

• The hydraulic circuit is for '96 - '98 models. On '99 - 01 models, the 2nd accumulator is different.ProCarManuals.com

Lock-up System

Lock-up Clutch

1. Operation (clutch on)

With the lock-up clutch on, the fluid in the chamber between the torque converter cover and the lock-up piston is drained

off, and the converter fluid exerts pressure through the piston against the torque converter cover. As a result, the converter

turbine is locked to the converter cover. The effect is to bypass the converter, thereby placing the vehicle in direct drive.

LOCK-UP PISTON

TORQUE CONVERTER

COVER
DAMPER SPRING

TURBINE

2. Operation (clutch off)

With the lock-up clutch off, the fluid flows in the reverse of CLUTCH ON. As a result, the lock-up piston moves away from

the converter cover, and the torque converter lock-up is released.

TORQUE CONVERTER

COVER
MAINSHAFT
DescriptionProCarManuals.com

In position in 2nd, 3rd and 4th, and position in 3rd, pressurized fluid is drained from the back of the torque converter

through a passage, causing the lock-up piston to be held against the torque converter cover. As this takes place, the main-

shaft rotates at the same speed as the engine crankshaft. Together with hydraulic control, the PCM optimizes the timing of

the lock-up system. Under certain conditions, the lock-up clutch is applied during deceleration in 3rd and 4th gear.

The lock-up system controls the range of lock-up according to torque converter clutch (lock-up control) solenoid valves A

and B, and the throttle valve. When torque converter clutch solenoid valves A and B activate, modulator pressure

changes. Torque converter clutch solenoid valves A and B are mounted on the torque converter housing, and are con-

trolled by the PCM.

NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.ProCarManuals.com

Description

Lock-up System (cont'd)

No Lock-up

The pressurized fluid regulated by the modulator works on both ends of the lock-up shift valve and on the left side of the

lock-up control valve. Under this condition, the pressures working on both ends of the lock-up shift valve are equal, and

the shift valve is moved to the right side by the tension of the valve spring alone. The fluid from the pump will flow

through the left side of the lock-up clutch to the torque converter; that is, the lock-up clutch is in OFF condition.

NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.ProCarManuals.com

Partial Lock-up

Torque Converter Clutch (Lock-up Control) Solenoid Valve A: ON Torque Converter Clutch (Lock-up Control) Solenoid

Valve B: OFF

The PCM switches the solenoid valve A on to release the modulator pressure in the left cavity of the lock-up shift valve.

The modulator pressure in the right cavity of the lock-up shift valve overcomes the spring force; thus the lock-up shift

valve is moved to the left side.

The line pressure is then separated into the two passages to the torque converter:

Torque Converter Inner Pressure: enters into right side to engage lock-up clutch

Torque Converter Back Pressure: enters into left side to disengage lock-up clutch

The back pressure (F2) is regulated by the lock-up control valve, whereas the position of the lock-up timing valve is deter-

mined by the throttle B pressure, tension of the valve spring, and pressure regulated by the modulator valve. Also the posi-

tion of the lock-up control valve is determined by the back pressure of the lock-up control valve and torque converter pres-

sure regulated by the check valve. With the torque converter clutch solenoid valve B kept off, the modulator pressure is main-

tained in the left side of the lock-up control valve; in other words, the lock-up control valve is moved slightly to the right side.

This slight movement of the lock-up control valve causes the back pressure to be lowered slightly, resulting in partial lock-up.

NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.ProCarManuals.com