Subaru XT 1988 Service Manual page 555

AUTOMATIC TRANSMISSION AND DIFFERENTIAL
3-2
(2)
Output Signal Name and Function
Signal name
Function
Sh ift solenoids 1, 2
Controls sh ift stage by turning solenoid ON/OFF. Relationship between solenoid
operation and shifting stage is shown in Table below. When shifting, timing is con-
trolled for each solenoid to reduce shock.
Shift solenoid 3
Controls 3-2 shift timing and overrunning clutch operation. Shift timing is con-
(Overrunning clutch)
trolled by controlling release speed of oil pressure to reduce shock while down-
shifting. The overrunning clutch is controlled so that it will operate during coasting
to apply engine brake.
Duty solenoid A
Regulates the line pressure according to driving conditions.
(line pressure)
Duty solenoid B
Regulates the hydraulic pressure of the lock-up clutch and operates in three modes
(lock-up) (open, smooth and lock-up).
Duty solenoid C
Regulates the hydraulic pressure of the transfer clutch and controls the driving
(transfer pressure) force to the rear drive shaft.
"Power" indicator light
Indicates whether the shift pattern is "Normal" or "Power". The indicator lights
in power mode. This light is also used for "self-diagnosis".
"2nd range" indicator light
Lights when the "1st hold switch" turned OFF in "2" range.
"1st hold" indicator light
Lights when 1st speed is achieved with the "1st hold switch" turned ON and shift
lever set to "2" range.
ATF temperature warning light
Lights when ATF becomes hot (exceeds a set temperature level). (4WD only)
(3) Relationship Between Solenoid Operation and Shift Position
Shift position Shift solenoid 1 Shift solenoid 2 Shift ratio
0 0
1 st
X 0
2nd
"D" range
X X
3rd
0 X
4th
0
0
1st
"3" range X
0
2nd
X X
3rd
0
0
1 st
1 st hold released
X 0
2nd
X X
3rd
"2" range
0 0
1 st
1 st hold appl ied X 0
2nd
X X 3rd
0: Energized X :
Not energized
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