🔧 Highlander - Automatic Transmission Fluid (ATF) Drain & Refill

Your Highlander uses Toyota WS “sealed” automatic transmission fluid, which is checked by temperature and an overflow/check plug (not a dipstick). The job is a drain-and-refill (not a full “flush”), then setting the fluid level at the correct ATF temperature so shifting and transmission life stay healthy.

Difficulty Level: Advanced | Estimated Time: 1.5-3.0 hours

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⚠️ Safety & Precautions

• ⚠️ Support the Highlander on jack stands on a level surface; the transmission level check is only accurate when level.
• ⚠️ ATF can be hot. Wear gloves and safety glasses.
• ⚠️ Engine must run during the level-setting step—keep hands/clothes away from moving parts.
• ⚠️ Do not overfill. Incorrect level can cause slipping, harsh shifts, or leaks.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Safety glasses
• Nitrile gloves
• Drain pan (10-quart minimum)
• Shop rags
• Metric socket set (8mm-19mm)
• 10mm socket
• 3/8" drive ratchet
• 1/2" drive breaker bar
• Torque wrench (10-80 ft-lbs range)
• Hex/Allen bit socket set
• Fluid transfer pump (specialty)
• OBD2 scan tool with ATF temperature data (specialty)
• Infrared thermometer

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid (Toyota ATF WS) - Qty: 4-6 quarts
• Transmission drain plug gasket/crush washer - Qty: 1
• Transmission overflow/check plug gasket - Qty: 1
• Transmission fill plug gasket - Qty: 1
• Brake cleaner - Qty: 1

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📋 Before You Begin

• Park on a level surface, set the parking brake, and place wheel chocks behind the rear wheels.
• Raise the Highlander and support it on jack stands so it sits level (front-to-rear and side-to-side).
• Plan your temperature check: you’ll set the fluid level with the ATF between 35–45°C (95–113°F).
• Tip: Remove the fill plug first. If it’s stuck and you already drained the ATF, you’ll be stranded.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Access the transmission pan area

• If equipped with an under-cover, remove it using a 10mm socket and 3/8" ratchet.
• Place a drain pan under the transmission.

Step 2: Loosen the ATF fill plug (do this first)

• Locate the transmission fill plug on the transaxle case.
• Loosen it using the correct size from your hex/Allen bit socket set (or metric socket set, depending on plug style) with a breaker bar.
• Once you confirm it will come out, snug it back by hand for now.

Step 3: Drain the old ATF

• Remove the transmission drain plug using the correct size from your metric socket set (8mm-19mm) and a 3/8" ratchet.
• Let the ATF fully drain into the drain pan.
• Tip: Measure what drains out. It helps you refill close.

Step 4: Reinstall the drain plug with a new gasket

• Clean the drain plug and surrounding area using shop rags and brake cleaner.
• Install a new drain plug gasket/crush washer.
• Reinstall the drain plug using a torque wrench.
• Torque to 49 Nm (36 ft-lbs).

Step 5: Fill with Toyota WS ATF

• Remove the fill plug fully using your hex/Allen bit socket set (or appropriate socket).
• Use a fluid transfer pump (specialty) to pump Toyota ATF WS into the fill port.
• Fill until fluid starts to dribble back out of the fill port, then install the fill plug finger-tight.

Step 6: Warm the ATF and circulate it

• Start the engine (keep the Highlander safely on jack stands).
• With your foot on the brake, slowly move the shifter through P-R-N-D-S, pausing 2–3 seconds in each position, then return to P.
• Connect your OBD2 scan tool with ATF temperature data (specialty) and monitor ATF temperature.
• Target temperature window for level check: 35–45°C (95–113°F).
• Tip: An IR thermometer is a backup. Scan data is best.

Step 7: Set the final ATF level using the overflow/check plug

• Locate the transmission overflow/check plug (part of the level-check system).
• With the engine running and ATF at 35–45°C (95–113°F), remove the overflow/check plug using the correct tool from your hex/Allen bit socket set (or metric socket set).
• Correct level looks like this:
  • If a steady stream comes out, wait until it slows to a thin stream/drips.
  • If nothing comes out, install the overflow/check plug, add more ATF through the fill port using the fluid transfer pump (specialty), then re-check.
• Install a new overflow/check plug gasket and reinstall the overflow/check plug using a torque wrench.
• Torque to 20 Nm (15 ft-lbs).

Step 8: Torque the fill plug and reinstall covers

• Install a new fill plug gasket, then reinstall the fill plug using a torque wrench.
• Torque to 39 Nm (29 ft-lbs).
• Reinstall any under-cover using a 10mm socket and 3/8" ratchet.
• Lower the Highlander using the floor jack.

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✅ After Repair

• Test drive 10–15 minutes. Verify smooth shifts and no flare/slip.
• Check for leaks around the drain plug, overflow/check plug, and fill plug.
• If you have a scan tool, recheck for any transmission codes and confirm fluid temperature readings look normal.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $50-$120 (parts only)

You Save: $130-$400 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-2.5 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.