Transmission Procedures

This page lists 16 maintenance procedures for transmission (driveline, axles & brakes), drawn from HIT Srl's internal procedure library extracted from manufacturer service manuals.

HIT Srl supplies driveline, axle and brake spare parts for this class of machine.

General guidance only — always follow the operation and maintenance manual for your specific machine.

Transmission

• What is the correct sequence to calibrate the automatic gear shift on a powershift transmission using the torque-converter heat-mode method?

  Applies to one transmission alternative; a different transmission alternative uses a separate heat-mode calibration procedure, described separately.

  1. Park the machine on level ground, engage neutral, and apply the parking brake; run the engine at idling speed.
  2. Select automatic gear shifting from the setup menu.
  3. Select CALIBRATION and confirm.
  4. Select the heat mode and confirm.
  5. Raise the temperature in the transmission: apply the parking brake so the machine is stationary; select a travel direction (forward or backward) and apply half to maximum acceleration for 20 seconds; engage neutral and apply half throttle for 10 seconds at idling speed; repeat these two steps until the oil temperature is over 60°C and no more than 90°C, at which point the temperature display starts to flash.
  6. Check that the gear control is in neutral position.
  7. Select the transmission calibration menu and confirm.
  8. Start calibration by selecting the forward travel direction.
  9. Wait for the temperature check: if the temperature is below 60°C the display shows a hold message; once all conditions are met, the calibration process starts and the transmission activates different gears during calibration.
  10. Wait through the calibration process, which takes approximately 15 minutes, during which the display cycles through clutch and mode indicators.
  11. If the engine speed is too low or too high for the current calibration mode, adjust the throttle pedal position until the display indicates the speed is within limits; the calibration proceeds automatically once the engine speed has been within limits for about three seconds.
  12. After successful completion, the calibration results are stored in flash memory and a completion message is shown on the display (a blinking line for any clutch indicates its calibration was not successful).
  13. Turn off the ignition to store the values.

  Notes:

  • Do not leave the machine during calibration; the machine may start to move.
  • If the machine starts to move during calibration, use the foot brake to keep it stationary.
  • The transmission calibration process can be interrupted at any time by moving the shift lever into the reverse position.

• What is the correct sequence to calibrate the automatic gear shift using the stall heat-mode method?

  Applies to a different transmission alternative than the torque-converter heat-mode calibration procedure described separately.

  1. Park the machine on level ground, engage neutral, and apply the parking brake; run the engine at idling speed.
  2. Select automatic gear shifting from the setup menu.
  3. Select CALIBRATION and confirm.
  4. With the engine running, confirm to activate heat mode (the parking brake and clutch disengagement signals are temporarily disconnected to allow heat mode, and the highest possible gear is always selected).
  5. Heat the transmission with it stationary: stall the transmission for 15 seconds using the parking brake, then select neutral to flush and cool the oil for 10 seconds; repeat until the oil reaches the desired temperature of 70°C, at which point the temperature value on the display starts to flash.
  6. With the engine running, press Enter to proceed to the next menu.
  7. Check that all requirements are met — transmission in neutral, parking brake applied, oil temperature at 70°C — before proceeding to the next menu.
  8. Wait while the calibration process runs; the display shows information about the calibration procedure and any fault messages.
  9. During calibration, engine speed is automatically regulated to the default value suited to the transmission; once calibration is complete, the display shows a message to switch off the ignition for 5 seconds to save the new parameters.
  10. If inching is installed and the engine is switched off, an inch pedal calibration step is shown: depress the pedal slowly and keep it depressed until the display changes to a release message, then release the pedal slowly.
  11. After successful calibration, switch off the ignition for 5 seconds to save the new parameters.

  Note: Do not leave the machine during calibration; the machine may start to move.

• How is the transmission oil level checked?

  1. Check the oil level every day, at a temperature between 82-93°C with the engine running at low revs.
  2. Confirm the oil level is at the FULL reference mark.

• How often should transmission oil, filter, and level be checked or changed?

  Periodicity: Check oil level daily; change the oil filter every 500 hours; change the oil every 1500 hours.

  1. Perform a daily check to ensure the oil level is on FULL.
  2. Change the oil filter every 500 hours.
  3. Change the oil every 1500 hours.

  Notes:

  • Check the transmission oil level at a temperature of 82-85°C with the motor running at low revs.
  • Allow the transmission to cool before performing any maintenance.

• How is the torque converter breather filter cleaned?

  1. Put the machine in service position.
  2. Disconnect the breather filter from the transmission.
  3. Clean the breather filter of dirt.

  Confirmed across independent manufacturers’ manuals.

• What is the correct sequence to change the transmission oil and oil filter?

  1. Operate and warm up the transmission oil.
  2. Put the machine in service position.
  3. Place a receptacle under the transmission.
  4. Remove the drain plug for transmission oil and let the oil drain into the receptacle.
  5. Place a collection container under the oil filters.
  6. Clean the area around the oil filters.
  7. Remove the oil filters.
  8. Install the new oil filters, wetting the O-ring on the new filters with transmission oil, tightening to contact and then another two-thirds of a turn.
  9. Once the transmission oil has drained, fit the drain plug, making sure the washer for the oil plug is included.
  10. Remove the transmission dipstick and fill new transmission oil through the dipstick's hole to the low-level marking.
  11. Start the engine and let it idle for at least two minutes.
  12. Check that the drain plug for transmission oil seals tight.
  13. Remove the collection container, handling the oil and oil filters as environmentally hazardous waste.
  14. Check the transmission oil level with the engine running at idle and top up to the low-level marking.
  15. Warm up the transmission so the oil temperature is 63-73°C, checking the temperature using the operating menu.
  16. Check the oil level and top up to the max-level marking.

  Notes:

  • The transmission must not be overfilled.
  • Avoid skin contact with the oil; use protective gloves, since hot oil may cause burns, rashes and irritation.

• How is the transmission oil level checked and topped up?

  1. Check the oil level with the engine at idle, the transmission in neutral, and at operating temperature (approximately 85°C), wiping off the dipstick before checking; the level should be between the MAX and MIN markings.
  2. Fill transmission oil as needed, to the correct volume.
  3. Fill the oil while the transmission is at operating temperature, then wait a while and check the dipstick again.

  Notes:

  • Avoid prolonged skin contact with the transmission oil; use protective gloves.
  • Work carefully when filling to prevent other fluids or particles from contaminating the oil, which risks transmission damage.

• What is the correct sequence to calibrate the transmission?

  1. Park the machine on level ground, engage neutral, and apply the parking brake; run the engine at idling speed.
  2. Navigate to the service menu to select the function to calibrate, then press Enter.
  3. Enter the calibration code, obtained from the machine manufacturer's support (the code determines which service menu is activated: Diagnostics, Initiation or Calibration).
  4. Select the DRIVE-TRAIN group and confirm with Enter.
  5. Scroll to DRIVE-TRAIN menu 4.
  6. Check that the oil temperature is 61°C; if too low, warm the transmission: apply the footbrake so the machine is stationary; select forward travel direction and apply maximum acceleration for 20 seconds; engage neutral and apply maximum acceleration for 10 seconds at idling speed; repeat until the oil is hot (if engine speed drops toward the end of heating because the gearbox oil is too hot, maintain neutral and an engine speed of 1200 rpm for 20 seconds).
  7. Once the temperature is correct, the mode changes from 0 to 1; select DRIVE-TRAIN menu 3 (gearbox tuning, calibration of transmission couplings).
  8. Check that the gear control is in neutral position.
  9. Start calibration by pressing Enter.
  10. Wait through the calibration process, which takes approximately 15 minutes, during which engine speed is raised to approximately 770 rpm and the transmission activates different gears.
  11. Once engine speed decreases to idling and the phase indicator reaches 4, calibration is complete.
  12. Turn off the ignition to store the values.

  Notes:

  • Do not leave the machine during calibration; the machine may start to move.
  • If the machine starts to move during calibration, use the footbrake to keep it stationary.
  • Calibration can be aborted at any time by selecting reverse travel direction.

• What is the correct sequence to check the transmission oil level?

  Periodicity: Daily.

  1. Check the oil level with the engine at idling speed and the oil temperature between 82 and 93°C.
  2. Maintain the oil level at the FULL mark.

• What is the correct sequence to change the gearbox oil and filter?

  This should be carried out when the oil is at normal working temperature (82-93°C).

  1. Remove the gearbox drain plug and drain the oil.
  2. Release the suction strainer, withdraw it, and clean the strainer gauze, investigating the cause before topping up with new oil if metal particles are found.
  3. Fit a new gasket to the suction strainer and fit the strainer.
  4. Unscrew the filter bowl, remove the filter, and fit a new filter element.
  5. Fit the new filter and tighten it.
  6. Fit the drain plugs and tighten them.
  7. Fill with oil to the MIN mark on the dipstick.
  8. Start the engine and run it at 500-600 rpm until the oil has reached working temperature and the hoses, cooler and torque converter have been filled with oil.
  9. Keep the engine running at idling speed, check the oil level, and top up to the MAX mark on the dipstick.

  Note: In the event of gearbox damage, always replace the oil cooler too, since the damage may have been caused by a faulty oil cooler.

• What is the correct sequence to check the pressures in the gearbox?

  The pressure should always be checked when the oil is at the normal working temperature of 82-93°C and the gearbox is in neutral.

  1. Check the converter outlet pressure, which should be above 1.7 bar at an engine speed of 2000 rpm, and must not exceed 4.9 bar when the engine is at top speed.
  2. Check the clutch pressure, which should be 17-20 bar with the parking brake set, oil temperature 82-93°C, engine at idle (400-600 rpm), shifting through direction and speed clutches.

  Note: When the check is carried out under identical conditions, the pressure must not vary by more than 0.4 bar between the various clutches.

• What is the correct sequence to change the transmission oil and oil filter?

  1. Operate and warm up the transmission oil.
  2. Put the machine in service position.
  3. Remove the drain plug and let the oil drain into the receptacle.
  4. Remove the suction strainer and clean the strainer cloth, investigating the cause if metal particles are caught before refilling with new oil.
  5. Replace the suction strainer's gasket.
  6. Once the transmission oil has flowed out, refit the suction strainer and the drain plug, making sure the washer for the drain plug is included.
  7. Remove the filter holder and change the oil filter, tightening to contact and then a further two-thirds turn.
  8. Fill new transmission oil through the oil filler point to the low-level marking on the dipstick.
  9. Start the engine and let it idle for at least two minutes.
  10. Check that the drain plug for transmission oil seals tightly.
  11. Check the transmission oil level with the engine running at idle, topping up to the low-level marking.
  12. Warm up the transmission so the oil temperature is approximately 85°C, checking the operating menu for oil temperature.
  13. Check the oil level again and fill to the MAX mark.

  Note: Do not over-fill the transmission.

• What is the correct sequence to check the transmission oil level?

  1. Check the oil level with the engine idling, the transmission in neutral, and at operating temperature (approximately 85°C on the display); the level should be at the MAX marking on the dipstick, which should be wiped off before checking.
  2. Fill transmission oil at the filler point if needed, then wait a while and check again on the dipstick.

  Notes:

  • Wear gloves, since the oil dipstick is long.
  • Work carefully when filling, to prevent other fluids or particles from contaminating the oil and risking transmission damage.

• What is the correct sequence to check the transmission oil level?

  The operations described must be carried out by suitably trained and qualified personnel, working in conditions of maximum cleanliness and safety.

  1. With the engine idling, bring the transmission to normal operating temperature (80-110°C).
  2. Move the gear selector through all its positions to fill the clutches and oil passages.
  3. Park the machine on a flat surface, apply the parking brake, and put the gear selector in neutral, leaving the engine at minimum idle.
  4. Check with the dipstick that the oil reaches the MAX mark.
  5. If it does not, add oil through the filler tube (which also houses the dipstick) until the MAX mark is reached; if the oil quantity is excessive, drain it via the drain plug on the underside of the gearbox case until the MAX mark is reached, then refit the drain plug.
  6. After checking, reposition the dipstick correctly in the filler tube and tighten fully, since its end also acts as a plug.

  Notes:

  • If the level is too low, the converter and clutches are not sufficiently supplied and this could damage the transmission or cause poor performance.
  • If the level is too high, the oil foams and causes overheating.

• What is the correct sequence to change the transmission oil filter cartridges?

  The first cartridge replacement on a new transmission must be carried out after the first 100 operating hours; thereafter, replace by no later than the indicated interval, since a clogged cartridge stops filtering all circulating oil.

  1. Turn off the engine, apply the parking brake, and put the gear selector in neutral.
  2. Place a suitable oil-collection container under the filters.
  3. Unscrew the old cartridges with the appropriate wrench.
  4. Carefully clean the cartridge seats on their support.
  5. Lubricate the gaskets of the new cartridges with the same oil used in the transmission.
  6. Screw the new cartridges on by hand until the gaskets touch the support, taking care not to pinch them, then tighten a further half turn.
  7. After replacing the cartridge, check the oil level again with the engine idling, and check there are no oil leaks.

  Note: Never use containers or filling tools that have previously held antifreeze or engine coolant for transmission oil; these solutions contain ethylene glycol which, if introduced into the transmission, could cause the clutch discs to fail.

• What is the correct sequence to change the transmission oil?

  1. Drain the oil into a suitable container by unscrewing the drain plug on the underside of the gearbox case.
  2. Withdraw the dipstick and disconnect a flexible hose from the heat exchanger.
  3. Let the oil drain completely from the transmission, then refit the drain plug and reconnect the hose to the heat exchanger.
  4. Introduce new oil through the filler tube, taking care not to let impurities enter the transmission.
  5. Once filled, check the level as previously described and verify there are no oil leaks.

  Note: Replace with the machine on level ground, the transmission warm, the engine off, the parking brake applied, and the gear selector in neutral.

Looking for general maintenance tips and checklists? See Driveline, Axles & Brakes.