Hydraulic Pressure Tests

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Ensure engine coolant and transaxle fluid levels are correct. Start and run engine until transaxle fluid and engine coolant are at normal operating temperatures. Connect a tachometer to engine, and position it so driver can view it. Raise and support vehicle so drive wheels rotate freely.
Note locations of hydraulic pressure ports on transaxle case. See Fig 1 . Remove appropriate pressure port plug, and install appropriate adapter and oil pressure gauge to each pressure port.
Measure hydraulic pressure at each pressure port, except the torque converter port, with engine speed at 2500 RPM in each gear position. If torque converter pressure is measured, engine speed should not exceed 1500 RPM. For pressure port specifications, refer to illustration. See Fig 2 . If pressure is within specification, go to next step. If pressure is not within specification, identify possible cause and repair as necessary. See HYDRAULIC PRESSURE DIAGNOSIS table.
Remove pressure gauge and adapters and install pressure port plugs.

Fig 1: Identifying Transaxle Hydraulic Pressure Ports

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Fig 2: Standard Transaxle Hydraulic Pressures

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HYDRAULIC PRESSURE DIAGNOSIS

Symptom

Probable Cause

All Pressures High

Incorrect Transaxle Control Cable Adjustment, Malfunction Of Regulator Valve

All Pressures Low

Incorrect Transaxle Control Cable Adjustment, Oil Pump Malfunction, Clogged External or Internal Oil Filter, Clogged Oil Cooler, Regulator Valve Malfunction, Relief Valve Malfunction, Incorrect Valve Body Installation

Abnormal Pressure In Reverse Only

Regulator Valve Malfunction, Clogged Orifice, Incorrect Valve Body Installation

Abnormal Pressure In 3rd Or 4th Only

Overdrive Solenoid Valve Malfunction, Overdrive Pressure Control Valve Malfunction, Regulator Valve Malfunction, Switch Valve Malfunction, Clogged Orifice, Incorrect Valve Body Installation

Abnormal Underdrive Pressure Only

⁽¹⁾ Malfunction Of Oil Seal "K", "L" Or "M", ⁽²⁾ Underdrive Solenoid Valve Malfunction, Underdrive Pressure Control Valve Malfunction, Check Ball Malfunction, Clogged Orifice, Incorrect Valve Body Installation

Abnormal Reverse Clutch Pressure Only

⁽¹⁾ Malfunction Of Oil Seal "A", "B" Or "C", Clogged Orifice, Incorrect Valve Body Installation

Abnormal Overdrive Pressure Only

⁽¹⁾ Malfunction Of Oil Seal "D", "E" Or "F", ⁽²⁾ Overdrive Solenoid Valve Malfunction, Overdrive Pressure Control Valve Malfunction, Check Ball Malfunction, Clogged Orifice, Incorrect Valve Body Installation

Abnormal Low-Reverse Pressure Only

⁽¹⁾ Malfunction Of Oil Seal "I" Or "J", ⁽²⁾ Low-Reverse Solenoid Valve Malfunction, Low-Reverse Pressure Control Valve Malfunction, Switch Valve Malfunction, Fail Safe Valve "A" Malfunction, Check Ball Malfunction, Clogged Orifice, Incorrect Valve Body Installation

Abnormal 2nd Brake Pressure Only

⁽¹⁾ Malfunction Of Oil Seal "G", "H" Or "O", ⁽²⁾ Second Solenoid Valve Malfunction, Second Pressure Control Valve Malfunction, Fail-Safe Valve "B" Malfunction, Clogged Orifice, Incorrect Valve Body Installation

Abnormal Torque Converter Pressure Only

Clogged Oil Cooler, ⁽¹⁾ Malfunction Of Oil Seal "N", ⁽²⁾ Torque Converter Clutch Solenoid Malfunction , Torque Converter Clutch Control Valve Malfunction, Torque Converter Pressure Control Valve Malfunction, Clogged Orifice, Incorrect Valve Body Installation

Pressure Applied To Element Which Should Not Receive Pressure

Incorrect Transaxle Control Cable Adjustment, Manual Valve Malfunction, Check Ball Malfunction, Incorrect Valve Body Installation

⁽¹⁾	Refer to illustration for seal locations. See Fig 3 .

⁽²⁾	Refer to illustration for valve body component locations. See Fig 4 .

Fig 3: Identifying Oil Seal Locations

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Fig 4: Identifying Valve Body Bolts & Solenoid Valves

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.