Massey Ferguson 4.X.40 – TRANS1: Issue With Speed Sensor Values (TRANS1)

The code indicates a discrepancy between the Theoretical Forward Speed Sensor (X482) and the Intermediate Speed Sensor (X483), depending on the transmission range currently engaged. The controller is detecting that the speed values reported by these two sensors do not mathematically align with the selected gear ratio, meaning one of the sensors is providing an inaccurate reading, or there is a mechanical slip.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 5400 Series
• 6400 Series
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S

1. 1

   Inspect the wiring harnesses and connectors for both the X482 (Forward Speed) and X483 (Intermediate Speed) sensors for corrosion, pushed-out pins, or chafed wires.

2. 2

   Check the sensor circuits for an open circuit, a short circuit to ground (0V), or a short circuit to +12V.

3. 3

   Remove the sensors and inspect the magnetic tips for metal shavings or debris that could cause erratic readings.

4. 4

   Verify the transmission hydraulic oil level and condition, as contaminated oil can interfere with sensor operation.

5. 5

   Use diagnostic software (such as Wintest) to monitor the live values of X482 and X483 while driving to identify which sensor drops out or provides erratic data during range shifts.

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, and disconnect the battery.

2. 2

   Locate the Sensors

   Locate the X482 and X483 sensors on the transmission housing (refer to the specific model's service manual for exact housing locations, as they vary between Dyna-4 and Dyna-6).

3. 3

   Removal

   Disconnect the electrical connector from the faulty sensor. Remove the retaining bolt and carefully pull the sensor straight out of the transmission housing.

4. 4

   Clean the Port

   Wipe the mounting port clean, ensuring no dirt or debris falls into the transmission.

5. 5

   Installation

   Lubricate the O-ring on the new genuine Massey Ferguson speed sensor with clean transmission fluid. Insert the sensor into the port and tighten the retaining bolt to the OEM torque specification.

6. 6

   Reconnection

   Reconnect the electrical harness, ensuring the connector clicks into place and is free of moisture.

7. 7

   Calibration/Clearing

   Reconnect the battery. Use the diagnostic tool to clear the 4.X.40 fault code from the TRANS1 module. Test drive the tractor through all ranges to verify the speed discrepancy does not return.