Case IH 72 – Transmission Controller (TCU / ECM): F/R Synchronizer Disengaged from Position or Transmission oil temperature is above 122 degrees C

The ECM attempts to change the position of the Forward/Reverse Synchronizer each time the key switch is turned to the 'ON' or 'START' position, but the synchronizer fails to engage.

• MX Maxxum
• TN Series
• MXM Series
• Magnum Series
• Puma Series
• Maxxum Series
• T8/TG Series

1. 1

   Check external levers and relay rods for incorrect adjustment (Code 72: F/R Synchronizer cause)

2. 2

   Check rod pivots for stiffness or partial seizure (Code 72: F/R Synchronizer cause)

3. 3

   Visually inspect the remote fender switch connector for pushed-back pins or corrosion (Misattributed PTO Switch cause)

4. 4

   Inspect the wiring harness for rodent damage or chafing between the fender switch and the TMF controller (Misattributed PTO Switch cause)

5. 5

   Check the alternator output at terminal 'W' to ensure the PTO controller is reading engine RPM (Misattributed PTO Switch cause)

6. 6

   Disconnect the remote PTO switch and measure continuity across the switch terminals when toggled to verify if the switch is internally shorted or open (Misattributed PTO Switch cause)

1. 1

   Adjust levers and rods

   Adjust the external levers and relay rods to the correct factory specifications (Code 72: F/R Synchronizer cause).

2. 2

   Lubricate pivots

   Lubricate all rod pivots (Code 72: F/R Synchronizer cause).

3. 3

   Replace synchronizer components

   If the code persists and the gearbox exhibits excessive noise, the transmission-gearbox must be removed to replace worn internal synchronizer components (Code 72: F/R Synchronizer cause).

4. 4

   Power down tractor

   Power down the tractor and turn the battery disconnect switch to the OFF position (Misattributed PTO Switch cause).

5. 5

   Locate switch

   Locate the remote PTO switch on the rear fender (Misattributed PTO Switch cause).

6. 6

   Disconnect connector

   Disconnect the 3-pin electrical connector (e.g., Connector 402F) from the back of the switch (Misattributed PTO Switch cause).

7. 7

   Remove switch

   Depress the retaining tabs on the switch body and push the switch out of the fender bezel (Misattributed PTO Switch cause).

8. 8

   Install new switch

   Insert the new OEM remote PTO switch into the bezel until it clicks into place (Misattributed PTO Switch cause).

9. 9

   Reconnect connector

   Apply dielectric grease to the 3-pin connector and reconnect it to the switch (Misattributed PTO Switch cause).

10. 10

    Clear fault codes

    Power up the tractor and clear any stored TMF fault codes via the instrument cluster or diagnostic tool (Misattributed PTO Switch cause).

11. 11

    Test PTO engagement

    Test the PTO engagement from both the cab and the remote fender switch to ensure interlock functions correctly (Note: operating both simultaneously will trigger a TMF 154 code) (Misattributed PTO Switch cause).