DIY Transmission Fluid Swap for the 2025 Toyota Tacoma UA80F Made Easy: A Personal Step-by-Step Guide

[TrdMarkey]

Not sure if this was shared in the group before and why I thought we need a thread for it. I get that not many 4th Gen owners know how to swap out the transmission fluid in their Tacoma's running on the UA80F 8-speed automatic transmission. It's not a very hard DIY job and this post is here to help, to show you how to drain and fill up the transmission with the Toyota WS ATF (World Standard) to keep your truck running well.

Tools

You will need a few tools like:

- 4–5 quarts of Toyota WS ATF

- Fluid transfer pump with a hose for side filling

- 5mm hex key (for the standpipe)

- 24mm socket (for the fill plug)

Step-by-Step Process

1. First, warm up your Tacoma’s transmission so the fluid flows well.

2. Next, turn on the engine and let it idle for a bit, letting the ATF get hot.

3. Then park your truck flat. This is key for checking the fluid level right later.

Now, it’s time to drain the used fluid...

4. Start by finding the overflow plug (a 5mm hex) at the bottom of the transmission pan. Put a pan under it, then take off the plug carefully. At first, you'll see a slow drip, due to the internal standpipe managing the flow. To fully drain the fluid, put a 5mm hex key in the overflow spot and undo the standpipe. You will see the old ATF flow out fast.

5. When it stops, put the standpipe back by hand, tighten it just enough to hold it without going too far. Now, look for the fill spot (24mm hex) on the driver’s side of the transmission case. Open it, and start pumping in new Toyota WS ATF with your pump. Keep going until you see fluid come out of the overflow spot, then wait until it slows to a drip. This means the pan is filled to the standpipe’s level. Then hand-tighten the overflow plug lightly.

6. To make sure the fluid level is just right, turn on the engine again, keep the truck in Park, and switch through all gears to spread the ATF. Then, open the overflow plug once more.

P.S: Just to note, if a bit of fluid comes out, you’re good. If none, add more ATF through the fill spot until it drips.

7. Finally, screw both the overflow and fill plugs to the set tightness from the maker, and you’re done.

Your Tacoma’s UA80F transmission is now fresh and ready for the road. Regular fluid changes help it shift well, which is another key tip to remember as well.