Case IH 68 – Transmission ECM: Synchronizer Shuttle (Reverse) Solenoid or ECM Driver is Short to 12 Volts

The system has detected that the circuit for the reverse synchronizer shuttle solenoid, or the driver inside the control module, has shorted to a 12-volt power source.

• JXC
• TN55
• TN65
• TN75
• TN95
• JX70U
• JX80U
• JX90U
• JX100U
• Farmall 65C
• Farmall 75C
• Farmall 85C
• Farmall 95C

1. 1

   Verify the Transmission Status Lamp; when active, the Hi (Rabbit) and Lo (Turtle) lamps will flash in an alternating manner

2. 2

   Inspect the wiring harness between the ECM connector (Connector 1, Pin 17) and the Synchronizer Shuttle (Reverse) Solenoid Coil terminal for an open circuit or a short to a 12V power source

3. 3

   Inspect connectors at the ECM and solenoid for bent pins, loose pins, or wire damage

4. 4

   Test across the solenoid coil terminals with a multimeter to check for an internal short to ground or an open circuit

1. 1

   Locate the Solenoid

   On the 32x16 transmission, the Synchronizer Shuttle (Reverse) and Hi-Lo (Forward) Solenoids are located on the bottom of the Power Shuttle Control Valve.

2. 2

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent further electrical shorts.

3. 3

   Disconnect the Harness

   Unplug the electrical connector from the Synchronizer Shuttle (Reverse) Solenoid.

4. 4

   Remove the Faulty Solenoid

   Unscrew and remove the faulty solenoid/electro-valve from the Power Shuttle Control Valve block.

5. 5

   Install the New Solenoid

   Thread the new solenoid valve into the control block and tighten to OEM torque specifications.

6. 6

   Reconnect and Reassemble

   Reconnect the electrical harness to the new solenoid. Reconnect the battery.

7. 7

   Clear Codes and Calibrate

   Use an Electronic Service Tool to clear the fault codes. Depending on the tractor model, a Power Shuttle Transmission Calibration may be required after replacing control valve solenoids.