Massey Ferguson 04.1.91 – Transmission Control Module (TRANS / TRANS1): Issue With Speed Sensor Values (TRANS)

The transmission control system is receiving implausible, missing, or out-of-range signals from one of the transmission speed sensors (such as the theoretical forward speed sensor, intermediate speed sensor, or input shaft speed sensor). The system detects a discrepancy between expected rotational speeds and the actual values being reported by the sensor.

• 4707
• 4708
• 4709
• 4710
• T4 (2015-2021)
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S

1. 1

   Visually inspect the wiring harness and connector leading to the transmission speed sensors for rub points, corrosion, or loose pins.

2. 2

   Perform a resistance test on the disconnected sensor (a healthy sensor typically reads 450 to 540 ohms when the tractor is stopped).

3. 3

   Perform a voltage test to ensure the sensor outputs an alternating voltage when the ring gear is rotating.

4. 4

   Check the clearance and adjustment depth of the sensor in the transmission housing.

1. 1

   Locate the Sensor

   Find the affected speed sensor on the transmission housing.

2. 2

   Adjust the Sensor

   Loosen the counter-nut on the sensor. Screw the sensor in fully until it bottoms out against the internal gear. Then, unscrew it exactly 3/4 of a turn and tighten the counter-nut to lock it in place. Test the tractor to see if the code clears.

3. 3

   Replace the Sensor

   If adjustment fails or the sensor is dead, disconnect the electrical harness, loosen the counter-nut, and unthread the old sensor.

4. 4

   Install the New Sensor

   Thread the new sensor into the housing. Use the same adjustment method: screw it in fully, back it out 3/4 of a turn, and tighten the counter-nut.

5. 5

   Clear Codes

   Reconnect the wiring harness and use a diagnostic tool to clear the fault codes from the tractor's computer so the system recognizes the new sensor.