Case IH F70 – Transmission Controller: Torque Damper Fault

Indicates a mechanical or signal discrepancy involving the torsional damper (torque damper) located between the engine flywheel and the transmission. The controller monitors the engine speed (via the Engine Torque/RPM sensor) and compares it to the transmission input/mid-speed sensors. If the torque damper fails mechanically (e.g., the internal springs break or the splined hub strips out), the transmission input shaft speed will no longer match the engine RPM, and the system will log the F70 fault.

• MXM
• Case IH MXM 120
• Case IH MXM 130
• Case IH MXM 140
• Case IH MXM 155
• Case IH MXM 175
• Case IH MXM 190
• Case IH Maxxum 100
• Case IH Maxxum 110
• Case IH Maxxum 115
• Case IH Maxxum 120
• Case IH Maxxum 125

1. 1

   Check for accompanying sensor codes: Look for codes F71 or F72 (Engine Torque/RPM Sensor open circuit/short to ground) and F73 or F74 (Transmission Mid Speed Sensor open circuit/short to ground). If these are present, diagnose the wiring or replace the sensors first.

2. 2

   Verify sensor installation: Ensure the engine RPM sensor and transmission speed sensors have not been accidentally swapped during previous maintenance (which would trigger codes F75 or F76).

3. 3

   Check sensor signals: Use an electronic service tool or the tractor's H-Menu diagnostic mode to monitor the live RPM output of the engine speed sensor versus the transmission mid-speed sensor. If the engine is running but the transmission input shows 0 RPM (or erratic RPMs) while in gear, the mechanical connection (the torque damper) has likely sheared.

1. 1

   Prepare the Tractor

   Park the tractor on a hard, level surface. Lower all implements to the ground, place all shift levers in neutral, and block the front and rear wheels.

2. 2

   Split the Tractor

   Disconnect all necessary hydraulic lines, electrical harnesses, and cab linkages crossing the engine-to-transmission bell housing. Support both halves of the tractor with splitting stands and separate the engine from the transmission.

3. 3

   Remove the Damper

   Unbolt the failed torque damper assembly from the engine flywheel.

4. 4

   Inspect Mating Components

   Thoroughly inspect the transmission input shaft splines for twisting, wear, or damage caused by the damper failure. Clean the flywheel surface.

5. 5

   Install the New Damper

   Bolt the new torque damper assembly to the flywheel. (Ensure bolts are torqued to OEM specifications based on the bolt grade—e.g., Grade 8.8 or 10.9).

6. 6

   Reassemble

   Roll the tractor halves back together, ensuring the transmission input shaft aligns smoothly with the new damper's splined hub. Reconnect all lines and harnesses.

7. 7

   Perform Transmission Calibration

   Because a mechanical repair was effected, you must recalibrate the transmission clutches and synchronizers. Start the engine, bring it to 1200 RPM, and enter the H1 calibration mode via the tractor's display to recalibrate the clutch packs.