Hydraulic Pressure Test Procedure

Pressure testing is a very important step in the diagnostic procedure. These tests usually reveal the cause of most transaxle problems.
Before performing pressure tests, be certain that fluid level and condition, and shift cable adjustments have been checked and approved. Fluid must be at operating temperature 65° - 93°C (150° to 200°F).

1. Install an engine tachometer
2. Raise vehicle on hoist which allows front wheels to turn, and position tachometer so it can be read.





3. Attach 690 kPa (100 psi) gauges and special tool L-4559-2 to ports required for test being conducted. A 2068 kPa (300 psi) gauge and special tool L-4559-2 (C-3293) are required for reverse pressure test. Test port locations are shown in illustration.

TEST ONE-SELECTOR IN LOW 1st GEAR
1. Attach pressure gauge to the low/reverse clutch tap.
2. Move selector lever to the L position.
3. Allow vehicle wheels to turn and increase throttle opening to achieve an indicted vehicle speed to 32 km/h (20 mph).
4. Low/reverse clutch pressure should read 793 to 1,000 kPa (115 to 145 psi).
5. This test checks pump output, pressure regulation and condition of the low/reverse clutch hydraulic circuit and shift schedule.

TEST TWO-SELECTOR IN DRIVE 2nd GEAR
1. Attach pressure gauge to the underdrive clutch tap.
2. Move selector lever to the 2 position.
3. Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed to 48 km/h (30 mph).
4. Underdrive clutch pressure should read 758 to 1,000 kPa (110 to 145 psi).
5. This test checks the underdrive clutch hydraulic circuit as well as the shift schedule.

TEST THREE-SELECTOR IN DRIVE, OVERDRIVE GEAR
1. Attach gauge to the underdrive clutch tap.
2. Move selector lever to the D position.
3. Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed to 48 km/h (30 mph).
4. Underdrive clutch pressure should read below 35 kPa (5 psi).
5. This test checks the underdrive clutch hydraulic circuit as well as the shift schedule.

TEST FOUR-OVERDRIVE CLUTCH CHECK
1. Attach pressure gauge to the overdrive clutch tap.
2. Move selector lever to the circle D position.
3. Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed to 32 km/h (20 mph).
4. Overdrive clutch pressure should read 517 to 655 kPa (75 to 95 psi).
5. Move selector lever to the 2 position and increase indicated vehicle speed to 48 km/h (30 mph).
6. The vehicle should be in second gear and overdrive clutch pressure should be less than 35 kPa (5 psi).
7. This test checks the overdrive clutch hydraulic circuit as well as the shift schedule.

TEST FIVE-SELECTOR IN DRIVE, OVERDRIVE GEAR
1. Attach pressure gauge to the 2/4 clutch tap.
2. Move selector lever to the D position.
3. Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 48 km/h (30 mph).
4. The 2/4 clutch pressure should read 517 to 655 kPa (75 to 95 psi).
5. This test checks the 2/4 clutch hydraulic circuit.

TEST SIX-SELECTOR IN DRIVE, OVERDRIVE
1. Attach pressure gauge to the torque converter clutch off pressure tap.
2. Move selector lever to the D position.
3. Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 80 km/h (50 mph).

CAUTION: Both wheels must turn at the same speed.

4. Torque converter clutch off pressure should be less than 35 kPa (5 psi).
5. This test checks the torque converter clutch hydraulic circuit.

TEST SEVEN-SELECTOR IN REVERSE
1. Attach pressure gauge to the reverse clutch tap.
2. Move selector lever to the reverse position.
3. Read reverse clutch pressure with output stationary (foot on brake) and throttle opened to achieve 1,500 r/min.
4. Reverse clutch pressure should read 1,138 to 1,620 kPa (165 to 235 psi).
5. This test checks the reverse clutch hydraulic circuit.

TEST RESULT INDICATIONS
1. If proper line pressure is found in any one test, the pump and pressure regulator are working properly.
2. Low pressure in all positions indicates a defective pump, a clogged filter, or a stuck pressure regulator valve.
3. Clutch circuit leaks are indicated if pressures do not fall within the specified pressure range.
4. If the overdrive clutch pressure is greater than 35 kPa (5 psi) in step (6) of Test Three, a worn reaction shaft seal ring is indicated.