🔧 Tundra - Transmission Fluid Drain & Level Set

On your Tundra, the correct way to “change” the automatic transmission fluid is typically a drain-and-fill, then setting the fluid level using the overflow/check plug at a specific fluid temperature. This prevents underfilling (slip/shift issues) or overfilling (foaming/leaks).

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

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⚠️ Safety & Precautions

• ⚠️ Work on a level surface; the level check is inaccurate if the truck isn’t level.
• ⚠️ Exhaust and transmission parts get hot—wear gloves and let it cool if needed.
• ⚠️ Use jack stands (rated 3-ton minimum); never rely on a jack alone.
• ⚠️ Keep engine running only with the area ventilated (CO risk).
• ⚠️ No battery disconnect is required for this service.

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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)
• 10mm socket
• 12mm socket
• 14mm socket
• 24mm socket
• 3/8" drive ratchet
• 3/8" drive extension (6")
• 5mm hex bit socket
• Torque wrench (10–80 ft-lbs range)
• Fluid transfer pump (hand pump)
• OBD2 scan tool that reads ATF temperature (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid (Toyota WS equivalent) - Qty: 6 quarts
• Transmission drain plug crush washer - Qty: 1
• Transmission fill plug crush washer - Qty: 1
• Transmission overflow/check plug crush washer - Qty: 1
• Brake cleaner - Qty: 1
• Shop towels - Qty: 1 pack

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Raise the front (and rear if needed) so the truck sits level on jack stands (rated 3-ton minimum).
• Make sure you have a way to read transmission fluid temperature with an OBD2 scan tool that reads ATF temperature (specialty). This is required for an accurate level set.
• Plan to loosen the fill plug before draining fluid (so you don’t get stuck with an empty transmission you can’t refill).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the skid plate(s)

• Use a 10mm socket and 12mm socket with a 3/8" drive ratchet to remove the fasteners.
• Set the skid plate(s) aside so you can access the transmission pan area.

Step 2: Locate the transmission service plugs

• Find the fill plug on the transmission case (typically a large hex-head plug). Use a 24mm socket to confirm fit.
• Find the drain plug on the transmission pan area. Use a 14mm socket to confirm fit.
• Find the overflow/check plug (a smaller internal/secondary plug used to set the level). Use a 5mm hex bit socket to confirm fit.

Step 3: Crack the fill plug loose FIRST

• Use a 24mm socket, 3/8" drive ratchet, and extension (6") to loosen the fill plug.
• Do not remove it completely yet—just confirm it will come out.

Step 4: Drain the old transmission fluid

• Position a drain pan (10-quart minimum) under the drain plug.
• Use a 14mm socket to remove the drain plug and let the fluid drain fully.
• Clean the drain plug and mating area using brake cleaner and shop towels.
• Install a new drain plug crush washer.
• Reinstall the drain plug and Torque to 20 Nm (15 ft-lbs) using a torque wrench.

Step 5: Fill with new WS fluid (initial fill)

• Remove the fill plug using a 24mm socket.
• Install the fluid transfer pump (hand pump) into the fill hole.
• Pump in automatic transmission fluid (Toyota WS equivalent) until it begins to spill back out of the fill hole.
• Install a new fill plug crush washer, then reinstall the fill plug finger-tight for now.

Step 6: Start the engine and circulate fluid

• With the truck still safely on jack stands (rated 3-ton minimum), start the engine.
• Hold the brake pedal and slowly move the shifter through P-R-N-D and back, pausing ~3 seconds in each position.
• Leave the engine idling in P.

Step 7: Bring ATF to level-check temperature

• Connect your OBD2 scan tool that reads ATF temperature (specialty).
• Watch the transmission fluid temperature and target 36–46°C (97–115°F) at idle.
• Too hot = wrong level reading. If you overshoot, shut off and allow it to cool back into range.

Step 8: Set the fluid level using the overflow/check plug

• With the engine idling and ATF temp in range, place the drain pan under the overflow/check area.
• Use a 5mm hex bit socket to remove the overflow/check plug.
• If fluid runs out in a steady stream, let it drain until it becomes a thin trickle/drip.
• If nothing comes out, reinstall the overflow/check plug, then remove the fill plug with a 24mm socket and pump in more WS fluid with the fluid transfer pump. Recheck by removing the overflow/check plug again.
• Install a new overflow/check plug crush washer, then reinstall the overflow/check plug and Torque to 20 Nm (15 ft-lbs) using a torque wrench.

Step 9: Final tighten the fill plug

• Use a 24mm socket to install the fill plug with the new crush washer.
• Torque to 39 Nm (29 ft-lbs) using a torque wrench.
• Clean any spilled fluid using brake cleaner and shop towels.

Step 10: Reinstall skid plate(s)

• Reinstall the skid plate(s) using the 10mm socket and 12mm socket.
• Snug fasteners evenly. If any bolts feel stripped or won’t tighten, stop and replace the hardware.

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✅ After Repair

• Road test: drive 10–15 minutes and verify normal shifting.
• Park on clean pavement and check for drips around the drain, fill, and overflow/check plugs.
• If you notice delayed engagement, flare shifts, or leaks, recheck the level using the same temperature-based procedure.

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💰 DIY vs Shop Cost

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

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

You Save: $130-$390 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.

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🎯 Ready to get started?

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