New Holland 7016 – Transmission Control Unit (TCU/TCM) or a general vehicle/chassis control module: Difflock Solenoid Stuck On

The control module has detected that the differential lock solenoid is remaining electrically energized when it should be off. The solenoid is in a permanently activated state, preventing the differential lock system from disengaging as required. This condition severely affects the vehicle's ability to turn properly, especially on hard surfaces.

• T5.85
• T5.95
• T5.100
• T5.105
• T5.115
• TD55D
• TD60
• TD60D
• TD65
• TD65D
• TD70
• TD70D
• TD75D
• TD80
• TD80D
• TD85D
• TD90
• TD90D
• TD95
• TD95D
• TL65
• TL70
• TL75
• TL80
• TL85
• TL90
• TL95
• TL100
• TL70A
• TL80A
• TL90A
• TL100A
• TD5010
• TD5020
• TD5030
• TD5040
• TD5050
• TD5.65
• TD5.75
• TD5.80
• TD5.85
• TD5.90
• TD5.100
• TD5.105
• TD5.110
• TD5.115
• 4835
• 5635
• 6635
• 7635

1. 1

   Visually inspect the wiring harness and connector at the differential lock solenoid for damage, corrosion, or loose connections. Ensure chassis and controller ground connections are clean and tight.

2. 2

   Listen for solenoid activation: With the machine in a safe state (parking brake engaged, engine off, key on), have an assistant operate the differential lock switch. An audible click indicates the coil is energizing but may be mechanically stuck. No click when deactivated suggests it is receiving continuous power.

3. 3

   Check voltage at the solenoid: Disconnect the harness connector. With the key on and switch disengaged, verify 0V (12V indicates a short to power or faulty module output). With the switch engaged, verify 12V.

4. 4

   Check solenoid resistance: Measure across the solenoid terminals. Expected resistance is between 6 and 8 Ohms. Infinite or very low resistance indicates a faulty solenoid coil.

5. 5

   H-Menu Diagnostics (If Applicable): On some New Holland tractors, access the diagnostic H-Menu via a special connector (sometimes requiring tool No. 4FT 950) to view and clear stored and active fault codes (menus HB and HD) and confirm if the 7016 code is currently active.

1. 1

   Ensure Safety

   Park the tractor on a level surface, engage the parking brake, turn off the engine, and remove the key. If necessary, disconnect the battery.

2. 2

   Locate and Remove the Solenoid

   The differential lock solenoid is typically located on the rear axle or transmission housing. It will have an electrical connector and will be threaded into a hydraulic valve body.

3. 3

   Address Wiring Issues

   If the diagnostic checks revealed a wiring fault (e.g., short to power), repair or replace the damaged section of the wiring harness.

4. 4

   Replace the Solenoid

   If the solenoid is confirmed to be faulty (incorrect resistance or mechanically stuck), unscrew it from the valve body. Be prepared for some hydraulic fluid to leak out.

5. 5

   Install the New Solenoid

   Lubricate the O-rings on the new solenoid with clean hydraulic fluid. Thread the new solenoid into place and tighten it to the manufacturer's specified torque. Reconnect the electrical connector.

6. 6

   Clear Fault Codes

   After the repair, use the H-Menu or a compatible diagnostic tool to clear the 7016 fault code.

7. 7

   Test Operation

   Start the tractor and test the differential lock system to ensure it engages and disengages correctly. Check for any hydraulic fluid leaks from the new solenoid.