🔧 Highlander - Automatic Transmission Fluid Drain & Fill

This procedure replaces part of the automatic transmission fluid in your Highlander using the drain-and-fill method. Your Highlander uses a sealed Toyota 8-speed automatic transmission, so there is no dipstick; the fluid level must be checked at the correct fluid temperature through the overflow/check plug.

Difficulty Level: Intermediate | Estimated Time: 1.5-2.5 hours

---

⚠️ Safety & Precautions

• ⚠️ Keep the vehicle level when draining and setting fluid level; an uneven vehicle can cause the wrong fluid level.
• ⚠️ Transmission fluid gets hot enough to burn skin. Wear gloves and safety glasses.
• ⚠️ Support your Highlander with jack stands only. Never work under a vehicle held up by a jack alone.
• ⚠️ The exhaust and transmission case may be hot after driving. Let them cool before touching nearby parts.
• ⚠️ Battery disconnect is not required for this repair.
• ⚠️ Do not flush the transmission with a machine unless specifically directed by Toyota service information; this guide covers drain-and-fill only.

---

🔧 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
• 10mm socket
• 14mm socket
• 24mm socket
• 6mm hex bit socket
• 3/8-inch drive ratchet
• 1/2-inch drive ratchet
• Torque wrench (5-75 ft-lbs)
• Fluid transfer pump (specialty)
• Scan tool with transmission fluid temperature data (specialty)
• Drain pan (10-quart minimum)
• Measuring container with quart markings
• Infrared thermometer
• Shop towels

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Toyota WS automatic transmission fluid - Qty: 4-5 quarts
• Transmission drain plug gasket - Qty: 1
• Transmission fill plug gasket - Qty: 1
• Transmission overflow/check plug gasket - Qty: 1

---

📋 Before You Begin

• Park your Highlander on a flat, level surface.
• Set the parking brake and place wheel chocks behind the rear wheels.
• Raise and support the vehicle level using a floor jack and jack stands.
• A scan tool is required to read automatic transmission fluid temperature. This is important because the fluid expands as it warms up.
• Use only Toyota WS automatic transmission fluid. Mixing the wrong fluid can cause shifting problems.
• Before draining, always loosen the fill plug first. This prevents getting stuck with an empty transmission you cannot refill.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise and Level the Vehicle

• Use a floor jack to lift your Highlander at the proper front and rear lift points.
• Place jack stands under the approved support points.
• Use wheel chocks to keep the vehicle from rolling.
• Make sure the vehicle sits level front-to-back and side-to-side.
• Level matters for correct fluid level.

Step 2: Remove the Lower Engine Cover

• Use a 10mm socket to remove the bolts from the lower splash shield.
• Lower the cover and set it aside.
• Keep the bolts together so they go back in the same places.

Step 3: Find the Transmission Plugs

• Use a shop towel to clean around the transmission fill, drain, and overflow/check plug areas.
• The fill plug is on the side of the transmission case.
• The drain plug is at the bottom of the transmission pan area.
• The overflow/check plug is used to set the final fluid level. An overflow tube inside the transmission lets extra fluid drain out when the level is correct.

Step 4: Loosen the Fill Plug First

• Place the drain pan under the transmission area.
• Use a 24mm socket and 1/2-inch drive ratchet to carefully loosen the fill plug.
• Do not remove it fully yet; just make sure it can be opened.
• Never drain before confirming refill access.

Step 5: Drain the Old Fluid

• Move the drain pan directly under the drain plug.
• Use a 14mm socket to remove the transmission drain plug.
• Let the fluid drain until it slows to a drip.
• Use a measuring container with quart markings to measure how much fluid came out.
• This drained amount is your starting refill amount.

Step 6: Reinstall the Drain Plug

• Install a new transmission drain plug gasket on the drain plug.
• Thread the drain plug in by hand first to avoid cross-threading.
• Use a 14mm socket and torque wrench to tighten the drain plug.
• Torque to 39 Nm (29 ft-lbs)

Step 7: Add New Transmission Fluid

• Remove the fill plug fully using a 24mm socket.
• Use a fluid transfer pump to pump in the same amount of Toyota WS automatic transmission fluid that drained out.
• Add about 0.5 quart extra so the final level can be set through the overflow/check plug.
• Install a new transmission fill plug gasket.
• Thread the fill plug in by hand.
• Use a 24mm socket and torque wrench to tighten the fill plug.
• Torque to 39 Nm (29 ft-lbs)

Step 8: Warm the Transmission Fluid

• Connect the scan tool with transmission fluid temperature data to the diagnostic port under the dashboard.
• Start the engine while the vehicle remains level and safely supported.
• Hold the brake pedal firmly.
• Move the shifter slowly through P-R-N-D, pausing 3 seconds in each position.
• Return the shifter to Park.
• Watch the transmission fluid temperature on the scan tool.
• Target fluid temperature for level setting is approximately 35-45°C (95-113°F).

Step 9: Set the Fluid Level

• Keep the engine idling and the vehicle level.
• Place the drain pan under the overflow/check plug.
• Use a 6mm hex bit socket and 3/8-inch drive ratchet to remove the overflow/check plug.
• If fluid runs out in a steady stream, wait until it becomes a thin drip.
• If no fluid comes out, reinstall the overflow/check plug loosely, turn the engine off, add 0.25-0.5 quart through the fill hole using the fluid transfer pump, then repeat the level check.
• Correct level is reached when fluid comes out as a light trickle or drip at the target temperature.
• A thin drip means full.

Step 10: Reinstall the Overflow/Check Plug

• Install a new transmission overflow/check plug gasket.
• Thread the plug in by hand first.
• Use a 6mm hex bit socket and torque wrench to tighten the overflow/check plug.
• Torque to 20 Nm (15 ft-lbs)

Step 11: Check for Leaks and Reinstall the Cover

• Use a shop towel to wipe the transmission plug areas clean.
• With the engine still idling, look for leaks around the fill, drain, and overflow/check plugs.
• Turn the engine off.
• Use a 10mm socket to reinstall the lower engine cover.
• Snug the cover bolts firmly; do not overtighten plastic shield fasteners.

Step 12: Lower the Vehicle

• Use the floor jack to slightly lift your Highlander off the jack stands.
• Remove the jack stands.
• Lower the vehicle slowly to the ground.
• Remove the wheel chocks.

---

✅ After Repair

• Start your Highlander and let it idle for 1 minute.
• Shift through all gear positions once, then return to Park.
• Take a gentle 10-minute test drive. Avoid hard acceleration at first.
• Check for smooth shifts and no warning lights.
• Park on clean pavement and look underneath for leaks.
• Dispose of used transmission fluid at a recycling center or parts store that accepts used oil and ATF.

---

💰 DIY vs Shop Cost

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

DIY Cost: $60-$120 (parts only)

You Save: $190-$330 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.

---

🎯 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.