John Deere 521933.07 – GPM: Gear 4 Fault / Gear 4 Has Not Been Engaged After Several Attempts By The Module

This diagnostic trouble code (DTC) is generated when the control software detects that, after several automated attempts, Gear 4 cannot be engaged. The system determines this is likely a mechanical problem with the gear engagement mechanism. As a safety and preservation measure, Gear 4 is disabled and made unavailable until the next time the tractor is started.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6135R

1. 1

   Restart the tractor to see if the gear can be selected or if the fault is hard-coded.

2. 2

   Check for related electrical codes (521933.05 or 521933.06) to determine if the issue is strictly electrical (wiring or solenoid) rather than mechanical.

3. 3

   Verify the transmission hydraulic fluid level and condition, as low or heavily contaminated fluid can prevent hydraulic shift actuators from engaging the gear.

4. 4

   Check for code 521933.17 (Time-Out When Engaging Gear 4), which indicates the shift is taking too long but might not be completely failing.

1. 1

   Clear and Retest

   Clear the GPM codes and operate the tractor to command a shift into Gear 4.

2. 2

   Inspect Wiring and Solenoid

   Locate the Gear 4 shift solenoid on the DirectDrive transmission valve body. Inspect the harness for chafing, corrosion, or loose pins.

3. 3

   Test the Solenoid

   Ohm-test the Gear 4 shift solenoid to ensure it is within OEM specifications. If the solenoid is sticking mechanically but passing electrical tests, it may need to be replaced.

4. 4

   Mechanical Inspection

   Because the .07 suffix specifically points to a mechanical problem with the gear, if the solenoid and hydraulics are functioning properly, the transmission will require internal inspection.

5. 5

   Internal Transmission Repair

   A certified technician will need to split the tractor or access the DirectDrive gear cassette to inspect the Gear 4 synchronizer, shift fork, and clutch packs for excessive wear or mechanical failure.