New Holland 2816 – TCM: Transmission Pressure Accumulator Discharged

The Transmission Control Unit (TCU) has detected a loss of pressure in the accumulator circuit. The transmission regulated pressure accumulator has lost its nitrogen pre-charge (gone 'flat') due to a ruptured internal diaphragm or bladder, causing it to fill with hydraulic oil. Because it can no longer cushion pressure changes, the transmission system experiences pressure fluctuations resulting in jerky shifting, surging under load, or delayed gear engagement.

• T6010
• T6020
• T6030
• T6040
• T6050
• T6060
• T6070
• T6080
• T6090
• T7.170
• T7.175
• T7.185
• T7.190
• T7.200
• T7.210
• T7.220
• T7.225
• T7.230
• T7.235
• T7.245
• T7.250
• T7.260
• T7.270
• T7030
• T7040
• T7050
• T7060
• T8.275
• T8.300
• T8.320
• T8.330
• T8.350
• T8.360
• T8.380
• T8.390
• T8.410
• T8.420
• TL70
• TL80
• TL90
• TL100
• TM115
• TM120
• TM125
• TM130
• TM135
• TM140
• TM150
• TM155
• TM165
• TM190
• TS90
• TS100
• TS110
• TS115

1. 1

   Verify symptoms by checking if the tractor exhibits harsh or jerky gear changes, which is a primary indicator of a failed accumulator

2. 2

   Check transmission oil level and condition to ensure it is at the correct level and not contaminated

3. 3

   Visually inspect the accumulator and surrounding hydraulic lines for any signs of fluid leaks

4. 4

   Perform a pressure test to check the accumulator's ability to hold a charge (e.g., attempt to charge with nitrogen gas; if hydraulic oil is expelled, the internal diaphragm has ruptured)

1. 1

   Relieve hydraulic pressure

   Ensure the tractor is on level ground with the parking brake engaged. Relieve the hydraulic pressure from the transmission system, as accumulators store energy even when the engine is off.

2. 2

   Access the accumulator

   Locate the transmission accumulator. On many models, such as the T7 series, the accumulator is accessed by removing the right-hand rear wheel.

3. 3

   Remove the old accumulator

   Clean the area around the accumulator to prevent contamination. Carefully detach the hydraulic lines, loosen the retaining screws or mounting brackets, and remove the accumulator from the tractor.

4. 4

   Install the new accumulator

   Carefully thread the new accumulator into place, ensuring not to cross-thread the connections. Re-attach the hydraulic lines and secure the accumulator with its mounting hardware.

5. 5

   Perform post-installation checks

   Start the tractor and run it through all the transmission ranges, carefully checking for any leaks around the new accumulator and its connections.

6. 6

   Calibrate the transmission (Electro Command)

   With the tractor off, press and hold both the up and down gear shift buttons. Start the engine, then release the buttons. Release the clutch pedal and move the gear lever to the front position (C&D gears). Move the shuttle lever to the forward position. Press the 'bunny' (automatic function) button to enter synchronization mode ('syn'). Press and hold the 'turtle' button until 'End' is displayed. The system will prompt for C1, C2, C3, and C4 clutch calibrations. For each, press and hold the 'turtle' button until 'End' appears. Turn off the engine to store the values.

7. 7

   Calibrate the transmission (Power Command)

   Engage the handbrake, place the shuttle lever in neutral, and depress the clutch. Press and hold the upshift and downshift buttons while starting the engine. Release the buttons after starting. Carefully release the clutch pedal. Set engine RPM to approximately 1200. Select each clutch pack and hold the downshift button to calibrate it individually. Once all packs are calibrated, turn off the engine and wait at least 10 seconds to store the new values.

8. 8

   Calibrate the transmission (Auto Command CVT)

   With the handbrake on and shuttle in neutral, hold down the clutch, press and hold the upshift and downshift buttons, and then start the engine. Release the buttons. Carefully release the clutch. Press the upshift button twice (if oil temperature is correct, 'CL' will be displayed). Press the upshift button again to display 'Dt'. Depress the clutch and move the shuttle lever to forward, then release the clutch. Briefly press the auto switch. The engine speed will increase to 1200 RPM, and the clutches will calibrate automatically one by one. When 'End' appears, turn off the engine and wait 10 seconds for the values to be stored.