Toyota 4Runner Transmission Fluid Change: A Step-by-Step DIY Guide

Hey everyone! Today, I’m walking you through a straightforward transmission fluid change on our 5th Gen 2015 Toyota 4Runner. If you're like us, you appreciate the satisfaction of taking care of your vehicle with your own hands.

At TenFootStripes, we’re all about slowing down to notice the details—like the fact that "lifetime fluid" is usually a myth. Keeping fresh fluid in these transmissions is the best way to ensure they reach that legendary 300,000-mile mark. This is one of those maintenance tasks that, once you get the hang of, you’ll wonder why you ever paid a dealership to do it. From the correct Toyota ATF WS fluid to the specific torque specs, I’m breaking down everything you need to get the job done right at home. Let’s dive in!



Using Toyota Genuine ATF WS (World Standard) fluid. For a drain and fill on the 2015 4Runner, you’ll typically need about 4 quarts.

Tools Required for the 4Runner Transmission Fluid Change

• Fluid Transfer Pump: This makes adding fluid a breeze.
• 5mm Allen Wrench: For loosening and retightening the check plug.
• Thin Wall 24mm Socket: To handle the fill plug.
• 14mm Socket: For the drain plug.
• A pan to catch the old fluid in and a way to measure it.
• A way to read transmission temperature. I used Torque Pro on our Android tablet and a Bluetooth OBDII reader.

Torque Specs Used

• Drain plug - 180 lb-in/15 lb-ft (14mm)
• Overflow plug - 180 lb-in/15 lb-ft (5mm Allen)
• Fill plug - 27 lb-ft (24mm or 15/16")

Parts Needed

• Transmission Pan Drain Plug Crush Washer (35178-30010): Always replace this to ensure a proper seal.
• Transmission Pan Check Plug Crush Washer (35178-30010): Same as above, don’t reuse the old one.
• 5 Quarts of Toyota WS Transmission Fluid: There might be better but I know this works. I knew I would only need 4 for the drain and fill but I got an extra because I’m clumsy :)

Draining The Transmission Fluid

First things first—make sure your 4Runner is parked on level ground and the engine is cold. We will need to monitor the transmission’s temperature later and starting cold makes this easier. There are three plugs you’ll be dealing with: drain, check, and fill. Here’s how to approach them:

1. Pro-Tip: Always remove the Fill Plug first: If you drain the transmission and then realize the fill plug is seized or stripped, you’re officially stranded. Save yourself the headache—ensure you can get fluid in before you let any out.
2. Loosen and Retighten the Check Plug: Next, grab your 5mm Allen wrench and loosen the check plug. Once you’ve confirmed that it can come out, retighten it for now. This step helps you avoid any nasty surprises later, like a stripped plug.
3. Remove the Drain Plug: Finally, take your 14mm socket and remove the drain plug completely. Let the fluid drain out into your pan. It might take a few minutes, so take this time to enjoy the process—after all, you’re saving money and keeping your 4Runner in top shape.
4. Reinstall Drain Plug: Once it’s all drained, reinstall the drain plug with a fresh crush washer and tighten it up.

Filling the Transmission Fluid

Now that the old fluid is out, it’s time to get some fresh Toyota WS transmission fluid in there.

1. Measure the Old Fluid: I measured the old fluid by pouring it into a gallon jug with quart markings. I drained about 3.5 quarts out of the transmission.
2. Remove the Fill Plug: If you haven’t already, take the fill plug out with your 24mm socket.
3. Add Transmission Fluid: Using your Fluid Transfer Pump, start adding the new transmission fluid. Transfer as much back in as what you measured in step 1. Go slow and steady.
4. Reinstall the Fill Plug: Once you’ve got the fluid in, put the fill plug back in place and tighten it.

Setting the Transmission Fluid Level

This last part is key to ensuring your transmission fluid is at the perfect level.

1. Start the Engine: With everything buttoned up, start the engine and let it idle for 15-20 seconds. This gets the fluid circulating.
2. Shift Through the Gears: Shift from Park to Reverse, to Neutral, to Drive, and then back up through the gears to Park. Do this a few times, pausing for a couple of seconds in each gear.
3. Monitor Fluid Temperature: Let the engine idle in Park and keep an eye on the transmission fluid temperature. You’re wanting it to be 104-113 degrees Fahrenheit (or about 40-45 degrees Celsius). If it’s not there yet, you can let it idle in gear or gently brake torque the engine in gear to build up heat more quickly.
4. Check Fluid Level: Once you’re in the right temperature range, pull the check plug back out of the transmission pan. If any excess fluid drains out, let it run until it slows to a trickle then reinstall the check plug with a new crush washer. If nothing comes out, your fluid level is too low. You will need to let the 4runner cool and start over from step 2 of Filling Transmission Fluid.
5. Finish Up: Once the fluid is at the right level and the check plug is reinstalled with a new crush washer, you’re all done!

While You're Here...

If this guide helped you save a few bucks (and your sanity) in the driveway, you might enjoy my other over-engineered projects at Base Camp. When I’m not elbow-deep in transmission fluid, I’m usually finding ways to make our rig smarter.

Check out how I built a DIY camper GPS integration—it’s not a tracker, but a localized sensor that feeds live location data into our camper's Home Assistant so our dashboard always has accurate weather and time zone info as we travel. You can also see how I handled a recent AT&T loyalty scam. Whether it’s 4Runner maintenance or smart-camper automations, life is always easier when you have a plan!