Massey Ferguson 04.00.42 – TRANS: Transmission Hydrostatic Speed/Direction Sensor Issue or Transmission Output Speed Sensor Issue

The controller is receiving erratic, intermittent, or no signal from the sensor, which can result in harsh shifting, loss of auto-shift functionality, or failure to engage ranges properly.

• 7720S
• 7724S
• 7716
• 7720
• Tier 4 (2015-2021)
• 7718
• 7722
• 7722S
• 7715S
• 7718S
• 7715
• 7726
• 7719
• 7714
• 7724
• 7716S
• 7726S
• 4707
• 4708
• 4709
• 4710
• 5608-5613
• 5710SL-5713SL
• 7614-7626

1. 1

   Connect the Massey Ferguson service diagnostic tool and monitor 'inst ground speed - wheel' and 'inst trans output speed' while driving to see if the signal drops out, spikes erratically, or reads zero

2. 2

   Inspect the transmission harness and connector at the speed sensor for disconnections, chafed wires causing a short circuit, or corrosion inside the pins

3. 3

   Check for accompanying fault codes (such as CAN data link errors) that might indicate a broader harness issue rather than a localized sensor failure

1. 1

   Locate the Sensor

   The Transmission Output / Hydrostatic Speed Sensor is typically located on the side of the transmission housing or near the PTO cover.

2. 2

   Prep the Area

   Clean the area around the sensor to prevent dirt from entering the transmission housing. Depending on the sensor's exact location on your specific model, you may need to drain a portion of the transmission hydraulic fluid or be prepared to plug the hole quickly to minimize fluid loss.

3. 3

   Disconnect the Harness

   Unplug the electrical connector from the sensor.

4. 4

   Remove the Sensor

   Unbolt the retaining fastener and carefully pull the sensor out of the housing.

5. 5

   Install the New Sensor

   Lubricate the sealing O-ring on the new sensor with clean transmission fluid. Insert the sensor into the housing, ensuring it seats fully so the O-ring seals properly. Secure it with the retaining bolt.

6. 6

   Reconnect and Calibrate

   Plug the transmission harness back into the sensor. Clear the 04.00.42 fault code using the diagnostic tool and perform a test drive to verify that the transmission shifts smoothly and the speed registers correctly on the dashboard/service tool.