Massey Ferguson A.33.20 – Hydraulic/Transmission Control Unit: External Hydraulic Valve 3 Issue

Malfunction in the circuit or mechanical operation of the third rear remote hydraulic spool valve. The tractor's diagnostic system has detected that the valve is either not responding to commands, has an electrical open/short circuit at the solenoid, or is experiencing a pressure/flow discrepancy.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715(S)
• 7716(S)
• 7718(S)
• 7719
• 7720(S)
• 7722(S)
• 7724(S)
• 7726(S)

1. 1

   Verify the hydraulic/transmission fluid level and condition. Dirty oil or a blocked hydraulic filter can restrict flow and trigger valve faults.

2. 2

   Inspect the wiring harness leading to the Valve 3 solenoid at the rear of the tractor. Look for rubbed wires, broken pins, or corrosion inside the connector.

3. 3

   Use a multimeter to check the resistance of the Valve 3 solenoid coil. Check for an open circuit or a short to ground.

4. 4

   Swap the electrical connector (or the solenoid coil itself) from Valve 3 to Valve 2. If the fault code changes to Valve 2 (e.g., 0A.32.20), the solenoid is the culprit. If the code remains on Valve 3, the issue is in the wiring harness or the internal mechanical spool is stuck.

5. 5

   Ensure the quick-disconnect couplers on remote 3 are not damaged or blocked, which can cause dead-heading and pressure relief issues.

1. 1

   Depressurize the System

   Turn off the tractor and cycle the hydraulic levers/joystick to relieve all residual hydraulic pressure.

2. 2

   Disconnect Electricals

   Unplug the wiring harness connector from the Valve 3 solenoid.

3. 3

   Remove the Solenoid

   Remove the retaining nut or screws holding the solenoid coil to the valve body. Slide the coil off the valve stem.

4. 4

   Valve Body Replacement (If necessary)

   If the mechanical spool is scored or stuck, unbolt the Valve 3 section from the hydraulic valve stack. Carefully separate the slice, ensuring you do not lose the interconnecting O-rings.

5. 5

   Installation

   Install the new solenoid coil (or valve section with new O-rings). Tighten the retaining nut/bolts to OEM torque specs.

6. 6

   Reassembly & Testing

   Reconnect the electrical harness. Start the tractor, top up the hydraulic fluid, and operate the valve to bleed any trapped air.

7. 7

   Clear Codes

   Use a compatible diagnostic tool to clear the 0A.33.20 DTC from the system.