How to Change Car's Transmission Oil

Transmissions can be manual or automatic, front- or rear-wheel-drive. The thing they all have in common is that you need to change the fluid in them at regular intervals as specified by the manufacturer. Most automatic transmissions have pans that we drop to change the fluid, normally also changing a filter. However, there are transmissions, both manual and automatic, with drain plugs instead of pans.

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We're going to walk through the steps to change the oil in these transmissions.

Know How to Check Fluid Level and What Fluid to Use

 

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Most automatic transmissions have a dipstick to monitor the oil level in the transmission; some manual transmissions do as well. You can tell when a transmission that doesn't have a dipstick is full when the fluid begins to drip out of the fill opening. . How to fill and know when your transmission is full is something the owner's manual or the repair manual for your vehicle will tell you, as well as what fluid or oil to use. It will also list the transmission oil change interval specified by the manufacturer.

It's important not to overfill the transmission. Overfilling means that the fluid can get aerated and whipped into a froth, and frothy transmission fluid can't do a good job of lubricating and cooling internal parts. It's also really, really important to be certain of what fluid your transmission needs. At one time, there was Mercon, Dexron, Dexron II, and Type F, and those were about the only formulations of transmission fluid on the market. Today, there are more than a dozen varieties of ATF, each with additive packages of detergents, friction modifiers, and other agents that are custom-designed for specific makes and models. Using the wrong fluid can quickly damage or even wreck a transmission.

Source | Mike Aguilar

Vehicle System
Powertrain / Drivetrain
Skill Level
Beginner

This is a good project for new DIYers

Time to Complete
1 Hour
  1. Raise and support the vehicle. It should be as level as possible, or the transmission oil won't drain completely and you won't get an accurate reading of the level when you finish. Some vehicles, like the 2012 Honda Civic pictured above, have covers that you will need to remove to access the transmission.

    Change Transmission Oil

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  2. Locate and remove the transmission drain and fill plugs. The fill plug is removed now to vent the system and to ensure that it can be removed before the fluid is drained. The VW Golf pictured has a filler that is a bolt/plug, whereas the Honda previously shown has a dipstick.

    Change Transmission Oil

    Source | Mike Aguilar

  3. Allow the old oil/fluid to drain out.

    Change Transmission Oil

    Source | Mike Aguilar

  4. Replace the drain plug and insert the funnel into the fill opening. Most vehicles with the fill opening on the side will require a piece of hose or tubing between the bottle/funnel and the transmission. Advance Auto Parts also carries a pump that screws onto the bottle to handle this.

    Change Transmission Oil

    Source | Mike Aguilar

  5. Fill the transmission with the proper amount of the oil/fluid specified for your vehicle in the vehicle-specific repair manual for your particular year, make, and model. As the photo above shows, side-filling transmissions are full when the fluid drips out a little. Make sure you fill and check the level of the fluid with the vehicle on level ground, or the level will be incorrect.

  6. Replace any covers removed and take the vehicle for a quick test drive prior to rechecking the fluid level.

    Change Transmission Oil

     

    Fill and drain plug locations on a typical rear-wheel-drive transmission.

    Source | Mike Aguilar

  7. Pro Tip

    Don't forget to take advantage of the free oil-recycling program at Advance Auto Parts when you finish.

Last updated February 16, 2019

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