How to change your transmission fluid
Tom Vondrasek | 27th Feb 2024 | 6 minutes to read
Changing your vehicles automatic transmission fluid (ATF) is as important as doing an engine oil change. Transmission fluid degrades and changing it at the manufacturer’s recommended intervals (kilometres driven or time frame) is vital to keep the transmission working as it should. If you regularly tow with your vehicle, then changing it more often is a benefit.
Some vehicle automatic transmissions are sealed units and cannot be topped up or checked. It always pays to check what is covered by the manufacturer’s warranty if you have one of these units. Especially if you have an older, second-hand vehicle with high kilometres. I am sure it will require some type of servicing at some point.
Changing your transmission fluid is not as simple as changing engine oil. It is rewarding and will help your transmission last longer. It can require more specialised equipment depending on the transmission, so it pays to do your research first before rushing in and attempting it.
The process of changing automatic transmission fluid involves the following steps:
Tools & Materials
- Transmission Fluid
- Pan Gasket and Filter Kit (if applicable)
- Suction or Fluid Pump (if applicable)
- Ratchet, Socket Set, and Wrenches
- Hoist or Trolley Jack & Axle Stands
- Oil Drain Pan
- Safety Gear
Prepare the Vehicle
Take the vehicle for a short run to warm up the fluid. It flows better when warm. Park the vehicle on a level surface and engage the parking brake. Ensure the engine is off. Unless you have a hoist, jack up the car and put it on axle stands.
Locate the Transmission Pan
Locate the transmissions fluid pan under the vehicle. It's typically situated towards the rear of the engine and has bolts securing it to the transmission. It is the equivalent of the engines sump.
Drain the Fluid
Place the oil drain pan underneath the transmission pan. Either loosen and remove the bolts gradually, starting from one side to allow controlled drainage. Once the pan is loose, carefully tilt it to drain the old transmission fluid into the oil drain pan OR use the drain plug.
Clean the Transmission Pan
Thoroughly clean the transmission pan using a suitable solvent or cleaner. Remove any residue or debris to ensure a clean surface for reinstallation.
Replace the Filter and Gasket (if applicable)
If the vehicle has a replaceable transmission filter and gasket, remove and replace them according to the manufacturer's instructions. Ensure the new gasket is properly seated and secure.
Reinstall the Pan
Place the clean transmission pan back in position and carefully reinstall the bolts, tightening them evenly and gradually to avoid leaks.
Refill Transmission Fluid
Locate the transmission fluid dipstick or fill port. Use a funnel to pour the recommended amount of new transmission fluid into the transmission. Refer to the vehicle's manual for the appropriate fluid quantity.
Note: When draining a transmission there is still an amount of residual fluid left in it. When refilling, it is best to take note of what came out of the transmission and replace that amount with slightly less fluid. Then you can top it up to the required amount.
Check Fluid Level
Start the engine and let it idle for a few minutes. With your foot on the brake, select each gear in the transmission for a few seconds. This gets fluid in through all the gears. With the engine running, check the transmission fluid level using the dipstick. Add more fluid if needed to reach the recommended level on the dipstick.
Check for Leaks
Turn the engine off and check for any leaks. If no leaks, remove vehicle from hoist OR axle stands.
Test Drive and Recheck
Take the vehicle for a test drive to ensure smooth gear shifting and proper transmission operation. After the test drive, recheck the transmission fluid level and top up if necessary. Dispose of the old transmission fluid responsibly by taking it to a designated recycling centre or automotive service facility that accepts used fluids.
