Checking automatic transmission fluid

Part 1. Preparation and safety

Objective

• Check and adjust transmission and transaxle fluid for automatic transmissions.

Personal safety

Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:

• Work clothing - such as coveralls and steel-capped footwear
• Eye protection - such as safety glasses and face masks
• Ear protection - such as earmuffs and earplugs
• Hand protection - such as rubber gloves and barrier cream
• Respiratory equipment - such as face masks and valved respirators

If you are not certain what is appropriate or required, ask your supervisor.

Safety check

• Do not put your finger into the filler plug opening to check the fluid level whenever the transmission is rotating.
• If the vehicle has been driven prior to checking the fluid level, the fluid could be very hot. When you remove the filler plug this hot fluid may run out. Make sure you do not burn yourself on this hot fluid.
• Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.

Points to note

• You will need to refer to the owner's manual to find out where to check the oil level.
• A correct fluid level is critical to effective and efficient operation. If the level is too high, it will cause the fluid to churn and aerate, causing air bubbles that can trap heat and make the fluid run hotter. This can lead to early failure of bearings or gears.
• If the vehicle is not level when taking a reading, you may not get an accurate result.
• A low fluid level can cause as much of a problem as a high level. Air can enter the system and heat generation can burn vital internal components.
• Some automatic fluids expand quite a lot when they get hot, so it is extremely important to ensure the fluid level is correct at all temperatures.
• In the unlikely event that the fluid is over full when checking the automatic transmission system, and it has not been simply over filled at the time of service, it could indicate that water has entered the transmission through the transmission breather system. If this is the case, then the transmission fluid should be replaced.
• Color and condition of automatic transmission fluid:
  • Clean, uncontaminated fluid has a pinkish or reddish color
  • Fluid that has been overheated turns darkish brown or black
  • A white, milky appearance can mean the engine coolant is leaking into the transmission

Part 2: Step-by-step instruction

1. Prepare the vehicle
   Warm up the fluid by idling or driving the vehicle. Generally, automatic transmission designs use a dipstick to determine the correct transmission fluid level. Locate the dipstick and remove it, wipe it clean, examine the level marks and then insert it again. Refer to the shop manual to see what position the gear selector should be in, as different manufacturers specify different gear positions.
2. Check the fluid level
   Apply the foot brake and move the transmission selector through all the gear selections. This will allow all the cavities in the transmission to fill with new fluid, and check the fluid level in the specified condition by removing the dipstick and observing the fluid level on the dipstick. Adjust the level by adding the approved lubricant as necessary.