clutch NISSAN ALMERA 2001 User Guide

POWER TRANSMISSION=NJAT0013S02ªNº and ªPº PositionsNJAT0013S0201+ªNº position
Power from the input shaft is not transmitted to the output shaft because the clutches do not operate.
+ªPº position
Similar to the ªNº position, the clutches do not operate. The parking pawl engages with the parking gear
to mechanically hold the output shaft so that the power train is locked.
SAT991I
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-24

ª11º Position=NJAT0013S0202
+Forward clutch
+Forward one-way clutch
+Overrun clutch
+Low and reverse brakeAs overrun clutch engages, rear internal gear is locked by the operation of low and
reverse brake.
This is different from that of D
1and 21.
Engine brake Overrun clutch always engages, therefore engine brake can be obtained when
decelerating.
SAT374J
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-25

ªD1º and ª21º Positions=NJAT0013S0203
+Forward one-way clutch
+Forward clutch
+Low one-way clutchRear internal gear is locked to rotate counterclockwise because of the functioning of
these three clutches.
Overrun clutch
engagement conditions
(Engine brake)D
1: Overdrive control switch ªOFFº and throttle opening is less than 3/16
2
1: Always engaged
At D
1and 21positions, engine brake is not activated due to free turning of low one-
way clutch.
SAT377J
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-26

ªD2º, ª22º and ª12º Positions=NJAT0013S0204
+Forward clutch
+Forward one-way
clutch
+Brake bandRear sun gear drives rear planetary carrier and combined front internal gear. Front internal gear now
rotates around front sun gear accompanying front planetary carrier.
As front planetary carrier transfers the power to rear internal gear through forward clutch and forward
one-way clutch, this rotation of rear internal gear increases the speed of rear planetary carrier com-
pared with that of the 1st speed.
Overrun clutch
engagement conditionsD
2: Overdrive control switch ªOFFº and throttle opening is less than 3/16
2
2and 12: Always engaged
SAT378J
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-27

ªD3º Position=NJAT0013S0205
+High clutch
+Forward clutch
+Forward one-way
clutchInput power is transmitted to front planetary carrier through high clutch. And front planetary carrier is
connected to rear internal gear by operation of forward clutch and forward one-way clutch.
This rear internal gear rotation and another input (the rear sun gear) accompany rear planetary carrier
to turn at the same speed.
Overrun clutch
engagement conditionsD
3: Overdrive control switch ªOFFº and throttle opening is less than 3/16
SAT379J
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-28

ªD4º (OD) Position=NJAT0013S0206
+High clutch
+Brake band
+Forward clutch(Does not affect power
transmission)Input power is transmitted to front carrier through high clutch.
This front carrier turns around the sun gear which is fixed by brake band and makes
front internal gear (output) turn faster.
Engine brakeAt D
4position, there is no one-way clutch in the power transmission line and engine
brake can be obtained when decelerating.
SAT380J
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-29

ªRº Position=NJAT0013S0207
+Reverse clutch
+Low and reverse brakeFront planetary carrier is stationary because of the operation of low and reverse
brake.
Input power is transmitted to front sun gear through reverse clutch, which drives front
internal gear in the opposite direction.
Engine brakeAs there is no one-way clutch in the power transmission line, engine brake can be
obtained when decelerating.
SAT381J
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-30

Control System=NJAT0014OUTLINENJAT0014S01The automatic transaxle senses vehicle operating conditions through various switches and sensors. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
SWITCHES & SENSORS
cTCM
cACTUATORS
PNP switch
Throttle position sensor
Closed throttle position switch
Wide open throttle position
switch
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed sensor
Overdrive control switch
Stop lamp switchShift control
Line pressure control
Lock-up control
Overrun clutch control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-II communication line
control
Duet-EA controlShift solenoid valve A
Shift solenoid valve B
Overrun clutch solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
O/D OFF indicator lamp
CONTROL SYSTEMNJAT0014S02
SAT995J
OVERALL SYSTEM
Control System
AT-31

TCM FUNCTION=NJAT0014S03The function of the TCM is to:
+Receive input signals sent from various switches and sensors.
+Determine required line pressure, shifting point, lock-up operation, and engine brake operation.
+Send required output signals to the respective solenoids.
INPUT/OUTPUT SIGNAL OF TCMNJAT0014S04
Sensors, switches and solenoid
valvesFunction
InputPNP switch Detects select lever position and sends a signal to TCM.
Throttle position sensor Detects throttle valve position and sends a signal to TCM.
Closed throttle position switch Detects throttle valve's fully-closed position and sends a signal to TCM.
Wide open throttle position switchDetects a throttle valve position of greater than 1/2 of full throttle and sends
a signal to TCM.
Engine speed signal From ECM.
A/T fluid temperature sensor Detects transmission fluid temperature and sends a signal to TCM.
Revolution sensor Detects output shaft rpm and sends a signal to TCM.
Vehicle speed sensorUsed as an auxiliary vehicle speed sensor. Sends a signal when revolution
sensor (installed on transmission) malfunctions.
Overdrive control switchSends a signal, which prohibits a shift to ªD
4º (overdrive) position, to the
TCM.
Stop lamp switch Releases lock-up system when depressing pedal in lock-up condition.
OutputShift solenoid valve A/BSelects shifting point suited to driving conditions in relation to a signal sent
from TCM.
Line pressure solenoid valveRegulates (or decreases) line pressure suited to driving conditions in rela-
tion to a signal sent from TCM.
Torque converter clutch solenoid
valveRegulates (or decreases) lock-up pressure suited to driving conditions in
relation to a signal sent from TCM.
Overrun clutch solenoid valveControls an ªengine brakeº effect suited to driving conditions in relation to a
signal sent from TCM.
O/D OFF indicator lamp Shows TCM faults, when A/T control components malfunction.
Control MechanismNJAT0015LINE PRESSURE CONTROLNJAT0015S01TCM has various line pressure control characteristics to match the
driving conditions.
An ON-OFF duty signal is sent to the line pressure solenoid valve
based on TCM characteristics.
Hydraulic pressure on the clutch and brake is electronically con-
trolled through the line pressure solenoid valve to accommodate
engine torque. This results in smooth shift operation.
OVERALL SYSTEM
Control System (Cont'd)
AT-32

SAT003J
Normal ControlNJAT0015S0101The line pressure to throttle opening characteristics is set for suit-
able clutch operation.
SAT004J
Back-up Control (Engine brake)NJAT0015S0102If the selector lever is shifted to ª2º position while driving in D4(OD)
or D
3, great driving force is applied to the clutch inside the trans-
mission. Clutch operating pressure (line pressure) must be
increased to deal with this driving force.
SAT005J
During Shift ChangeNJAT0015S0103The line pressure is temporarily reduced corresponding to a
change in engine torque when shifting gears (that is, when the shift
solenoid valve is switched for clutch operation) to reduce shifting
shock.
At Low Fluid TemperatureNJAT0015S0104+Fluid viscosity and frictional characteristics of the clutch facing
change with fluid temperature. Clutch engaging or band-con-
tacting pressure is compensated for, according to fluid
temperature, to stabilize shifting quality.
SAT006J
+The line pressure is reduced below 60ÉC (140ÉF) to prevent
shifting shock due to low viscosity of automatic transmission
fluid when temperature is low.
OVERALL SYSTEM
Control Mechanism (Cont'd)
AT-33