Inspect Lock-Up Mechanism - Toyota MR2 1988 Repair Manual

AT-12
AUTOMATIC TRANSAXLE- Troubleshooting
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• Abnormal Noise
• Vibration
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• Engine Braking
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(c) Run in the OD gear of the D range and with the lock-
up in operation, and check for abnormal noise and
vibration.
NOTE: Check for cause of abnormal noise and vibration
must be made with extreme care as they could also be due
to unbalance in the drive shaft, differential, tire, torque
converter, etc. or insufficient bending rigidity, etc., in the
power train.
(d) While running in the D range 2nd, 3rd gears and OD,
check to see that the possible kick-down vehicle
speed limits for 2 - 1, 3 - 2, OD - 3 and OD - 2
kick-downs conform to those indicated on the
automatic shift diagram.
(e) Check for abnormal shock and slip at kick-down.
(f) While running about 80 km/h (50 mph) in the D
range OD gear, shift into the 2 and l ranges and
check the engine braking effect at each of these
ranges.
EVALUATION
(1) If there is no engine braking effect at the 2 range.
3rd Gear
Second brake is defective.
2nd Gear
Second brake and second .coast brake are defec-
tive.
(2) If there is no engine braking effect at the l range.
2nd Gear
Second brake and second coast brake are defec-
tive.
1st Gear
First and reverse brake are defective.
(g) While running in the D range, release your foot from
the accelerator pedal and shift into the l range. Then
check to see if OD - 3, 3 - 2 and 2 - 1 down-shift
points conform to those indicated on the automatic
shift diagram.
INSPECT LOCK-UP MECHANISM
(a) Connect a voltmeter to service connector terminals
ECT and E
1 •
(b) Select the normal pattern.
(c) Drive at around 50 km/h (31 mph) to where 7, 5 or 3
volts appears on the voltmeter (this is the lock-up
range).
(d) Depress the accelerator pedal and read the
tachometer. If there is a big jump in engine rpm there
is no lock-up.