Massey Ferguson 4.00.90 – TRANS1: Issue With Speed Sensor Values

The transmission controller is receiving erratic, implausible, or missing signals from the transmission speed sensor(s). When this occurs, the controller cannot accurately determine the transmission's output or internal speeds, which can lead to poor shifting, perceived transmission slippage, or the tractor engaging 'limp home mode'.

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

1. 1

   Inspect the wiring harness between the speed sensor and the Autotronic (TRANS1) box, ensuring all connections are clean, tight, and free of corrosion

2. 2

   Connect the tractor to Massey Ferguson Wintest diagnostic software and monitor transmission speed sensor values in real-time for dropouts or erratic fluctuations

3. 3

   Disconnect the sensor and use a multimeter to verify a 12V to 14V supply at the harness connector when the ignition is on

4. 4

   Remove the sensor and check the magnetic tip for excessive metal shavings that could distort speed readings

1. 1

   Park the tractor on a level surface, engage the parking brake, and turn off the engine.

   Ensure the tractor is safely parked before beginning repairs.

2. 2

   Locate the faulty transmission speed sensor on the transmission housing.

   Identify the sensor to be replaced.

3. 3

   Disconnect the electrical connector from the sensor.

   Carefully unplug the harness from the speed sensor.

4. 4

   Clean the area around the sensor thoroughly.

   This prevents dirt from entering the transmission housing when the sensor is removed.

5. 5

   Unbolt and carefully remove the old speed sensor.

   Note: Depending on the sensor's location on your specific model, you may need to partially drain the transmission fluid to prevent spills.

6. 6

   Inspect the old sensor for heavy metal accumulation.

   If heavily coated, a transmission oil and filter change is highly recommended.

7. 7

   Install the new speed sensor and tighten it to the OEM torque specification.

   Ensure the sensor is properly seated and torqued.

8. 8

   Reconnect the electrical harness.

   Plug the connector back into the new sensor.

9. 9

   Top off the transmission fluid if any was drained or lost.

   Restore fluid to the correct operating level.

10. 10

    Clear the fault codes and test drive the tractor.

    Use the Wintest software or the tractor's onboard diagnostic menu to clear codes, then test drive to verify the repair.