Automatic Transmission Road Test - Toyota HILUX 1993 Repair Manual

AT–24
AUTOMATIC TRANSMISSION
ROAD TEST
NOTICE: Perform this test at normal fluid temperature
(50–80SC or 122–176SF).
.
1 D POSITION TEST
Shift into the D position and while driving with the accel–
erator pedal held constant at the throttle valve full open
and the O/D switch ON, check on the following points:
(a) Check to see that the 1–2, 2–3 and 3–O/D up–shifts
take place and also that the shift points conform to
those shown in the automatic shift schedule.
HINT: 3–O/D up–shift does not take place with a
throttle valve opening of more than 86% or engine cool–
ant temperature below 50SC (122SF).
EVALUATION
(1) If there is no 1–2 up–shift:
(2) If there is no 2–3 up–shift:
(3) If there is no 3–O/D up–shift (throttle valve open–
(4) If the shift point is defective:
(b) In the same manner, check the shock and slip at
EVALUATION
If the shock is excessive:
(c) Run in the 3rd gear or O/D of D position and check
HINT: Check for cause of abnormal noise and vibration
must be made with extreme care as they could also be
due to unbalance in the propeller shaft, differential, tires,
torque converter clutch, etc.
– Troubleshooting (Mechanical System Tests
Governor valve is defective
1–2 shift valve is stuck
2–3 shift valve is stuck
ing less than 86%):
3–4 shift valve is stuck
Solenoid valve or circuit defective
Throttle cable out of adjustment
Throttle valve, 1–2 shift valve, 2–3 shift valve, 3–4
shift valve etc., are defective
1–2, 2–3 and 3–O/D up–shifts.
Line pressure is too high
Accumulator is defective
for abnormal noise and vibration.