Massey Ferguson 4.02.40 – TRANS1: Issue With Speed Sensor Values (TRANS1)

The transmission controller is detecting an anomaly, an implausible value, or a complete lack of signal from one of the transmission speed sensors (such as the theoretical forward speed sensor, input shaft speed sensor, or output shaft speed sensor).

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5709S
• 6613
• 6614
• 6615
• 6616
• 6713S
• 6714S
• 6715S
• 6716S
• 6718S
• 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 and connections between the sensor and the transmission controller for damage, corrosion, or loose pins

2. 2

   Perform a resistance test on the inductive speed sensor (e.g., TR4 sensor) using a multimeter with the tractor stopped (should read approximately 450 Ohms +/- 20)

3. 3

   Check for an alternating voltage signal from the sensor when the ring gear or shaft is rotating

4. 4

   Use diagnostic software (such as Wintest or Jaltest AGV) to monitor the sensor's status and output values in real-time to check for signal dropouts or erratic readings

5. 5

   Verify that the sensor is adjusted to the correct depth, as an incorrect air gap can cause signal loss

1. 1

   Disconnect the tractor's battery to prevent electrical damage.

   Preparation

2. 2

   Locate the transmission speed sensor, typically accessible from underneath the tractor, often located on the transmission input shaft or above the differential ring gear.

   Locate the Sensor

3. 3

   Clean the mounting area and electrical connector thoroughly to prevent dirt from entering the transmission. Disconnect the wiring harness, loosen the counter-nut, and unscrew the faulty sensor. (Note: Partially drain the transmission fluid if necessary depending on the exact sensor location).

   Removal

4. 4

   Apply a small amount of thread sealant (e.g., Loctite 5922) to the threads of the new sensor.

   Installation & Air Gap Adjustment

5. 5

   Fully screw the new sensor in until it bottoms out against the internal gear.

   Installation

6. 6

   Unscrew the sensor by exactly 3/4 of a turn to set the proper air gap.

   Air Gap Adjustment

7. 7

   Tighten the counter-nut to approximately 6 Nm to lock it in place.

   Tighten

8. 8

   Reconnect the electrical harness and reconnect the battery.

   Reassembly

9. 9

   Clear the stored 04.02.40 fault code from the system. Depending on the model, you may need to perform a transmission calibration (e.g., Dyna-4 or Dyna-6 calibration) to ensure the controller relearns the engagement parameters.

   Clear Codes and Calibrate