Torque Converter: Testing and Inspection

TORQUE CONVERTER STALL TEST
Stall test consists of determining maximum engine speed obtained at full throttle in "M and "R" positions. This test checks torque converter stator overrunning clutch operation, and holding ability of transmission clutches and low-reverse brake.

CAUTION: During this test, make sure that no one stands in front of, or behind, vehicle.

1. Check the transmission fluid level, fluid temperature and engine coolant temperature.
- Fluid level: At "HOT" position on dipstick
- Fluid temperature: 70-80°C (158-176°F)
- Engine coolant temperature: 80 - 90°C (176 - 194°F)
2. Apply chocks to both rear wheels.
3. Attach engine tachometer.
4. Apply parking and service brakes fully.
5. Start engine.
6. With selector lever in "M position, depress accelerator pedal fully to read engine maximum rpm. Do not hold throttle wide open any longer than is necessary to obtain maximum engine rpm reading, and never longer than 5 seconds at a time. If more than one stall test is required, operate engine at approximately 1,000 r/min in neutral for 2 minutes to cool transmission fluid between tests.
Standard value:
2,100 - 2,600 r/min
3,300 - 3,800 r/min
7. Place selector lever to "R" position and perform stall test by the same procedures above.

Stall Speed Above Specification in "D"
If stall speed is higher than specification, rear clutch overrunning clutch of transaxles slipping. In this case, perform hydraulic test to locate cause of slippage.

Stall Speed Above Specification in "R"
If stall speed is higher than specification, front clutch of transaxle or low-reverse brake is slipping. In this case, perform hydraulic test to locate cause of slippage.

Stall Speed Above Specification in "D" and "R"
It stall speed is lower than specification, insufficient engine output or faulty torque converter is suspected. Check for engine misfiring, ignition timing, valve clearance etc. If these are good, torque converter is faulty.