Mitsubishi Eclipse 1990, Service Manual

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AUTOMATIC TRANSAXLE
ENGINE (NON-TURBO)>
On-vehicle Service
TORQUE CONVERTER STALL TESTING
The torque converter stall test is used primarily to determine
overrunning clutch operation.
Use the scan tool and a tachometer to test.
Determine engine rpm with the transaxle in
at wide open throttle, and vehicle
To keep the vehicle stationary and to avoid creeping or lurching
forward, apply both the service brakes and the parking brake.
WARNING
When performing a stall test, always apply both the ser-
vice brakes and parking brake. Also, do not let anyone
stand in front of the vehicle during
NOTE
Avoid keeping the throttle open for more than 5 seconds
at a time. Allow the transmission fluid to cool
tests by placing the transaxle in neutral, raising the
rpm slightly for approximately 20 seconds.
TORQUE CONVERTER CLUTCH FAILURE
One type of over-running clutch failure is a slipping
clutch. With this type of failure, the will exhibit normal
transaxle operation at highway speeds will have poor
acceleration.
Another type of
over-running clutch failure is a seized
clutch.
With this type of failure, the vehicle acceleration may be ac-
ceptable but a high throttle is required to maintain vehicle
speed.
The vehicle may seem like it has a loss of power.
With either type of failure, poor fuel economy and transaxle
fluid over-hearting may be the result.
STALL SPEED ABOVE SPECIFICATION
If the stall speed exceeds 2,440 by more than 200
a clutch is slipping.
Diagnose the clutch circuits by performing hydraulic and air
pressure tests.
The clutches of the transaxles may also be checked
using information given through the input and output speed
sensors to the TCM.
STALL SPEED BELOW
SPECIFICATION
If stall speed is below specification, the
over-running clutch is slipping. During the road test, if poor
acceleration occurs through the gears with normal transaxle
operation at highway speeds, the vehicle has a slipping
clutch.
NORMAL STALL SPEED AND
ACCELERATION
If stall speed and acceleration appear normal, but it takes
excessively high throttle opening to maintain vehicle speed,
the starter’s over-running clutch is seized.
This will impede the flow of fluid within the torque converter,
causing excessive use of power from the engine for cruising.
CONVERTER NOISE
While performing the stall test, listen for abnormal noise com-
ing from the converter area.
A whining noise due to fluid flow within the converter is consid-
ered normal.
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