Massey Ferguson 04.02.08 – TRANS: Transmission High/Low Range Position Sensor Issue

The transmission control module is receiving an erratic, out-of-range, or missing electrical signal from the sensor responsible for monitoring whether the transmission is engaged in the high or low range (often referred to as the Hare/Tortoise range).

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 7700 Series
• 5400 Series
• 5700 Series
• 6400 Series
• 8600 Series

1. 1

   Check for related codes using a diagnostic tool to see if there are accompanying voltage errors (e.g., 8.5V or 12V reference supply drop out)

2. 2

   Inspect the wiring harness leading to the range position sensor on the gearbox for chafed wires, short circuits, or corrosion inside the connector

3. 3

   Test sensor voltage by disconnecting the sensor and testing the connector pins with a multimeter (Pin 1 should receive a steady 12V or 8.5V supply, Pin 2 is the signal return)

4. 4

   Verify mechanically that the transmission is shifting fully into range, as a worn dog clutch or synchronizer can cause an incomplete shift and an incorrect sensor reading

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, turn off the engine, and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the Sensor

   Locate the High/Low (Hare/Tortoise) range position sensor on the exterior of the gearbox housing.

3. 3

   Removal

   Depress the locking tab on the electrical connector and pull it free from the sensor. Clean the area around the sensor to prevent dirt from falling into the transmission. Unbolt or unscrew the faulty sensor from the transmission housing.

4. 4

   Installation

   Lubricate the O-ring on the new sensor with a small amount of clean transmission fluid. Thread the new sensor into the housing and tighten it to the OEM torque specification.

5. 5

   Reconnection

   Reconnect the electrical harness, ensuring it clicks securely into place. Reconnect the battery.

6. 6

   Calibration/Clearing

   Connect a diagnostic tool to clear the 04.02.08 fault code. Start the tractor and cycle the transmission through the High and Low ranges to ensure the code does not return and the controller registers the shifts.