GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC C-Series Medium Duty Truck B7 🢒 Transmission/Transaxle 🢒 Automatic Transmission - Allison 🢒 Transmission Fluid Check

Cold Oil Level Check Procedure

Important: 

   • Clean the area at the end of the oil level indicator tube prior to removal of the oil indicator.
   • Make sure that no dirt or debris enters the oil level indicator tube and transmission.
   • Do not overfill the transmission with oil. Overfilling the transmission causes internal damage to the transmission.
   • For early detection of transmission problems, check the following conditions at regular intervals:
      - The oil level
      - The oil color
      - The smell of the oil
      - The condition of the oil
   • When adding or changing the oil, use only DEXRON® III Transmission Oil. Refer to Fluid Capacity Specifications .
   • Check the oil on the oil level indicator at least twice. Consistency is important for maintaining accuracy.

  1. Position the vehicle on level ground.
  2. Engage the parking brake.
  3. Shift the transmission into neutral.
  4. Run the engine for at least 1 minute in order to remove air from the oil system.
    5. • Make sure the oil temperature is between 38-49°C (100-120°F).
    • Check the transmission oil level when the engine is running at idle.
  5. Remove the oil level indicator from the oil level indicator tube.

    6. Object Number: 201483 Size: SH
  6. Inspect the oil level indicator for the oil level reading.
    7. • If the indicator reads above the cold full level (4), drain some of the oil until the indicator reads at the cold level.
    • If the indicator reads at the cold full level (4), do not add oil. The transmission oil level is at the proper operating level.
    • If the indicator reads between the cold full (4) and cold add (3) levels, add oil until the oil level indicator reads at the cold full level.

Hot Oil Level Check Procedure

Important: 

   • Clean the area at the end of the oil level indicator tube prior to removal of the oil indicator.
   • Make sure that no dirt or debris enters the oil level indicator tube and transmission.
   • Do not overfill the transmission with oil. Overfilling the transmission causes internal damage to the transmission.
   • For early detection of transmission problems, check the following conditions at regular intervals:
      - The oil level
      - The oil color
      - The smell of the oil
      - The condition of the oil
   • When adding or changing the oil, use only DEXRON® III Transmission Oil. Refer to Fluid Capacity Specifications .
   • Check the oil on the oil level indicator at least twice. Consistency is important for maintaining accuracy.

  1. Position the vehicle on level ground.
  2. Engage the parking brake.
  3. Shift the transmission into neutral.
  4. Check the transmission oil level when the engine is running at idle.

    5. Important: Make the hot oil check after the transmission reaches the normal operating temperature of 71-93°C (160-200°F).

  5. Remove the oil level indicator from the oil level indicator tube.

    6. Object Number: 201483 Size: SH
  6. Inspect the oil level indicator for the oil level reading.
    7. • If the indicator reads above the hot full level (2), drain the oil until the indicator reads at the hot full level.
    • If the indicator reads at the hot full level (2), do not add oil. The transmission oil level is at the proper operating level.
    • If the indicator reads between the hot add (1) and the hot full (2) levels, add oil until the indicator reads at the hot full level (2).

Oil Level Adjustment Procedure

    Object Number: 201483 Size: SH
  1. About 0.946 liter (1 quart) of transmission oil raises the oil level from:
    2. • The cold add level (3) to the cold full level (4)
    • The hot add level (1) to the hot full level (2)
  2. The oil level should not be above the top of:
    3. • The cold full level (4) in a cold oil check
    • The hot full level (2) in a hot oil check
  3. Drain oil from the transmission in order to reduce the level of the oil as required.
  4. Add oil as required in order to attain the proper oil levels. Refer to either the hot oil check procedure or the cold oil check procedure above.