Hydraulic Pressure Test: Notes

WARNING: This page is about a different variant/trim than selected.

CAUTION: The transmission fluid temperature should be between 70 - 80°C (158 - 176°F) during the test.

Check the transmission fluid level and temperature. Check engine coolant temperature.
- Transmission fluid level: "HOT" mark on the dipstick
- Transmission fluid temperature: 70 - 80°C (158 - 176°F)
- Engine coolant temperature: 80 - 100°C (176 - 212°F)
Raise the vehicle so that the wheels are free to turn.
Connect the special tools (3.0 MPa (427 psi) oil pressure gauge [MD998330] and joint [MD998331, MB992127]) to each pressure discharge port.
NOTE: DR: Torque converter output pressure port
PRI: Primary pressure port
PL: Line pressure port
FWD: Forward clutch pressure port
REV: Reverse brake pressure port

Fig 1: Identifying Torque Converter Output Pressure Port, Primary Pressure Port, Line Pressure Port And Forward Clutch Pressure Port
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Restart the engine.
Check that there are no leaks around the special tool port adapters.
WARNING: For safety, operators must not stand in front of and at the rear of the vehicle during this test.
Measure the hydraulic pressure at each port under the conditions given in the standard hydraulic pressure table, and check that the measured values are within the standard value ranges.
If the pressure is not within the standard value, stop the engine and refer to the HYDRAULIC PRESSURE TEST DIAGNOSIS TABLE .

Fig 2: Identifying Reverse Brake Pressure Port
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Remove the O-ring from the port plug and replace it.
Remove the special tool, and install the plugs to the hydraulic pressure ports.

Start the engine and check that there are no leaks around the plugs.

STANDARD HYDRAULIC PRESSURE CHART

Measuring conditions		Standard hydraulic pressure MPa (psi)
Transmission range	Engine speed	Forward clutch pressure [Pressure at FWD]	Reverse brake pressure [Pressure at REV]	Primary pressure [Pressure at PRI]	Line pressure [Pressure at PL]	Torque converter [Pressure at DR]
P	Idling	0 (0)	0 (0)	0.1 - 1.5 (15 - 218)	0.5 - 1.5 (73 - 218)	0.1 - 1.0 (15 - 145)
R		0 (0)	0.5 - 1.0 (73 - 145)	0.1 - 1.5 (15 - 218)	0.5 - 1.5 (73 - 218)	0.1 - 1.0 (15 - 145)
N		0 (0)	0 (0)	0.1 - 1.5 (15 - 218)	0.5 - 1.5 (73 - 218)	0.1 - 1.0 (15 - 145)
D		0.5 - 1.0 (73 - 145)	0 (0)	0.1 - 1.5 (15 - 218)	0.5 - 1.5 (73 - 218)	0.1 - 1.0 (15 - 145)
L <Vehicles without sport mode>		0.5 - 1.0 (73 - 145)	0 (0)	0.1 - 1.5 (15 - 218)	0.5 - 1.5 (73 - 218)	0.1 - 1.0 (15 - 145)

HYDRAULIC PRESSURE TEST DIAGNOSIS CHART

Symptom	Faulty part
Hydraulic pressure is high at all measuring points.	Incorrect measuring method
Hydraulic pressure is low at all measuring points.	Malfunction of oil pump Clogged oil strainer Clogged oil cooler Malfunction in valve body assembly Improper installation of valve body assembly
Only forward clutch pressure is abnormal.	Malfunction in valve body assembly Improper installation of valve body assembly Faulty seal ring A
Only reverse brake pressure is abnormal.	Malfunction in valve body assembly Improper installation of valve body assembly
Only primary pressure is abnormal	Malfunction in valve body assembly Improper installation of valve body assembly
Only line pressure is abnormal.	Malfunction in valve body assembly Improper installation of valve body assembly
Only torque converter output pressure is abnormal	Malfunction in valve body assembly Improper installation of valve body assembly Malfunction of torque converter Faulty seal ring B