How to change the oil in an automatic transmission?

Learn how to change automatic transmission oil properly and additional considerations such as changing automatic transmission oil filters and other truck parts such as drain plug and cooling hoses.

What is automatic transmission oil?

A truck's automatic transmission works properly when the oil has the right lubricating properties and viscosity. For this reason, it is important to choose genuine truck additives and oils that ensure the unit's performance.

Automatic transmission oil performs several functions:

  •  Removes heat from the parts of the truck that increase its temperature.
  • Lubricating the bearings of the truck.
  • Serves as a working fluid for the truck's hydraulic system and converter.

When to change the automatic transmission oil?

The automatic transmission oil change interval is established by the manufacturer, however, this time period may be shortened by severe operating conditions, for example: driving in high temperature such as in deserts or dusty areas.

Some truck parts stores recommend changing automatic transmission oil more frequently than recommended by the manufacturer.

When the automatic transmission oil level is low, the gearbox will stop working properly.

How to check the oil level in an automatic transmission?

Use a special dipstick to measure the automatic transmission oil level, usually the engine oil dipstick is yellow and the automatic transmission oil dipstick is red.

  1. With the truck's engine running, remove the automatic transmission oil dipstick and wipe it with a clean cloth.
  2. Insert the automatic transmission oil dipstick, hold it for 10 seconds and pull it out.
  3. The oil level should be between the maximum and minimum indicators.

After performing the above steps, check the following characteristics of this truck fluid.

  • The automatic transmission oil should be light.
  • The color should be slightly dark.
  • The odor of the oil should be within the standards compared to a bottle or pail of truck oil.

When the automatic transmission oil is quite thicker, has a very dark color or there is an unpleasant burning odor, it is necessary to change the oil or go to a truck workshop.

Steps to change automatic transmission oil

Partial automatic transmission oil replacement

Make sure you have everything you need to perform the partial automatic transmission oil replacement such as: new truck oil, a small funnel and a measuring cup.

  1. Unscrew the drain plug on the automatic transmission.
  2. Place a container under the automatic transmission plug and drain the oil.
  3. When the container is empty, refill it with oil through the funnel.
  4. Insert the dipstick for automatic transmission oil.

In case you perform this procedure and put in too much automatic transmission oil, drain the excess through the plug.

Complete automatic transmission oil replacement

To perform a complete automatic transmission oil replacement, you will need to prepare the following truck additives and diesel parts (if necessary).

  •  New oil, measuring cup and funnel.
  • Truck gaskets and automatic transmission sealant.
  •  Drain plug ring.
  • Automatic transmission oil filter.
  • Truck bolt removal heads (check measurements).

Follow these steps to completely change the automatic transmission oil and purchase the new truck parts you require.

  1. Drain the current oil, then unscrew the truck bolts holding the pan and remove it from the sealant.
  2. Remove the oil filter from the truck and place it in a container.
  3. Clean the pan and magnets with a brush, making sure to remove the old truck gaskets. Then put the new oil filter for the truck.
  4. Degrease the installation site, install the gasket on the automatic transmission pan, place sealant and install it, then tighten the bolts.
  5. Measure how much oil was drained and pour the same amount into the automatic transmission with the help of the funnel.
  6. Identify the automatic transmission cooling hoses near the truck radiator. Disconnect the cooling hose near the truck's gear and place it in a pail.
  7. Ask another person to start the truck engine with the truck gearbox in neutral to draw the remaining oil from the automatic transmission pump through the hose. Drain the old oil until new automatic transmission oil comes out, you will be able to identify it because it is visually lighter.
  8. Turn off the truck engine, attach the cooling hose, measure the amount of oil drained and add the same amount to the automatic transmission.
  9. Finally, check that the truck oil level is between the maximum and minimum marks on the corresponding dipstick.

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