Stall Test; Measure Stall Speed; Evaluation - Toyota MR2 1988 Repair Manual

AT-8 AUTOMATIC TRANSAXLE- Troubleshooting
Stall Test
The object of this test is to check the overall performance of the transmission and engine by measuring the
maximum engine speeds in D and R ranges.
CAUTION:
(a} Perform the test at normal operating
fluid temperature (50 - 80°C or 122 -
176°F}.
(b} Do not continuously run this test
longer than 5 seconds.
MEASURE STALL SPEED
(a) Chock the front and rear wheels.
(b) Mount an engine tachometer.
(c) Fully apply the parking brake.
(d) Step down strongly on the brake pedal
with your left foot.
(e) Start the engine.
(f) Shift into D range. Step all the way
down on the accelerator pedal with your
right foot.
Quickly read the highest engine rpm at
this time.
Stall speed:
A240E/4A-GE 2,150
±
150 rpm
A241 E/4A-GZE 2,650 ± 150 rpm
(g) Perform the same test in R range.
EVALUATION
(a) If the engine speed is the same for both
ranges but lower than specified value:
• Engine output may be insufficient.
• Stator one-way clutch is not operat-
ing properly.
(b) If the stall speed in D range is higher
than specified:
• Line pressure too low
• Forward clutch slipping
• One-way clutch No. 2 not operating
properly
• UD one-way clutch not operating
properly
(c) If the stall speed in R range is higher
than specified:
• Line pressure too low
• Direct clutch slipping
• First and reverse brake slipping
• UD brake slipping
(d) If the stall speed in R and D ranges is
higher than specified:
• Line pressure too low
• Improper fluid level
• UD brake slipping
TE0047